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UC-NRLF

RADIUM AND RADIO-ACTIVE
SUBSTANCES

Their Application Especially to Medicine -

CHAS. BASKERVILLE, Ph. D.,

Professor of Chemistry and Diredlor of the Laboratory, College

of the City of New York, formerly of the University

of North Carolina.

Published by

Williams, Brown & Earle

918 CHESTNUT STREET, PHILADELPHIA, PA., U. S. A.

*ERAL

Copyrighted by

Williams, Brown & Earle,

1905.

ERNEST RUTHERFORD

WHOSE INVESTIGATIONS ON RADIO-ACTIVITY
ARE WORTHIER OF A HIGHER TRIBUTE

Q A

PREFACE.

To fill a demand for an inexpensive non-mathematical
work on the subject of radium and its application in medicine,
arrangements were made for the publication of this book.
At that time the excellent treatises of Rutherford and Soddy
had not appeared. To anyone purposing the prosecution of
investigations, these works are indispensable. One treats the
phenomena of radio-activity from the point of view of a
physicist, while the other looks at them more with the eyes of
a chemist. The appearance of these works has made it neces-
sary to alter this book somewhat. The technical details have
been given so admirably by these co-laborers that it has been
thought just as well to omit much here. This book emphasizes
a phase naturally but hinted at by them, namely, the applica-
tion of radio-active substances in medicine. The writer is
not in a position to harmonize the contradictory evidence given
in reputable medical journals as to the therapeutic uses of the
salts of radium, consequently the observations have been impar-
tially reported. Physicians of prominence, who ha-ve had
much to do with the use of this novel substance in their prac-
tice, have been good enough to revise the chapter bearing upon
that phase of the subject.

It has been deemed advisable for comparison to annex a
short chapter on other therapeutic radiations.

As many physicians will have neither the time nor the
opportunity to study the larger works, sufficient of the general
subject has been presented for a fairly clear conception of our
present knowledge of these startling, perhaps revolutionary,
phenomena.

Although the work makes no pretense at completeness, all
known sources of information have been freely drawn upon.
In most cases due credit has been given.

The bibliography, which was prepared, has been omit-
ted. A most complete index to the extensive literature of
radium by Dr. George F. Kunz is in press for the United States
Geological Survey.

Dr. Fritz Zerban and Mr. Frederick E. Breithut have gen-
erously followed the proof -sheets. Mr. N. R. Graham was
good enough to prepare the index.

New York, 1905.

TABLE OF CONTENTS.

Chapter Page

I. The Phenomenon of Radio- Activity, . . . i

II. The Extraction of Radium Salts ; Properties,

Physical and Chemical of Radium, . . 22

III. Other Radio- Active Substances ; Uranium, Tho-

rium, Polonium, Actinium, Carolinium,
Thorium X, Radio-Tellurium, Emaniutn,
and Radio- Active Lead. The Sources of
Radio-Activity, ...... 46

IV. The Emanations of Radium and Induced Radio-

Activity . Ex- Radio, . . . . 69

V. The Theories of Radio- Activity, ... 94

YI. The Physiological Properties and Therapeutic

Applications of Radio- Active Substance, . 115

VII. Other Therapeutic Radiations, . . . .142
Index, ... ..." . . .. .\ ". . . .153

Radium and Radio-Active Substances.

CHAPTER I.

THE PHENOMENON OF RADIO-ACTIVITY.

If there be one thing which may be said to characterize
science and its progress, it is evolution, or growth. Practi-
cally all the great movements of science and its modern mar-
vels are linked to the past. The phenomenon of radio-ac-
tivity, which has astonished a civilization accustomed to
wonders, is no exception.

Without going too far back, attention may be called to
the now well known fact that an electric spark passes through
the air in a zigzag line, the length of which varies with the
distance between the charged and uncharged bodies. The
intensity of the spark varies with the charge, a corresponding
difference being observed, as when the hand is passed over a
cat's fur or surcharged clouds relieve themselves in a violent
flash of lightning. The discharge presents a very different
appearance, however, when the air is rarified, as originally
investigated by Gassiott.

Geissler, of Bonn, was the first to imprison gases under
diminished pressure in tubes provided with electrodes, that is,
conducting terminals by which the discharge may be carried in
or cut. Geissler tubes are so exhausted that there exists an
internal pressure of about one-thousandth of an atmosphere.
The discharge, visibly passes (Fig. i) between the anode
(positive) and cathode (negative), the one terminal being of as

THE PHENOMENON OF RADIO-ACTIVITY.

much importance apparently as the other. Plucker has shown
that the color of the light produced is not dependent upon the
substance of the electrodes. It varies with the nature of the
gas or vapor, being crimson with hydrogen and purple-red
with nitrogen, and so on.

In 1876 Crookes made an elaborate investigation of the
phenomena produced by the electric discharge in much higher
vacua1. The pressure within the Crookes tubes is about one
thousandth that of the Geissler tubes, or one-millionth of an
atmosphere, and the path of the discharge is no longer visible.
The discharge is independent of the anode and appears to pro-
ceed from the cathode alone Ifi^f) . Further, the luminous

Fig. i. Fig. 2.

Fig. I. In a Geissler tube the discharge visibly passes between anode
and cathode, the location of the former being of little importance.

Fig. 2. In a Crookes tube the cathode rays are projected in straight
lines from its surface ; their presence is noted by the fluorescence of the
walls of the tube opposite the negative terminal.

effect upon the glass is directly opposite the cathode, which
indicates that these rays move in straight lines and strike upon
the glass exactly opposite that electrode. With the Geisslei

i. Phil. Trans. CLXX, 135, 641 ; Nature XX, 419, 436.

THE PHENOMENON OF RADIO-ACTIVITY. 3

tubes, on the other hand, the discharge may be made to follow
devious paths, depending upon the shape of the apparatus,
thus prod-ttctttg exquisite-effects'. — ('£ig,_lL

The production of light without any considerable heat
by the action of such rays was designated luminescence by E.
Wiedemann. The color of the light depends not upon the
gaseous contents of the tubes, but the solid material upon
which the rays impinge. Some diamonds, for example, glow
spterrdidly white, while coral gives an intensely brilliant red-
dish or purplish luminescence

Two other interesting properties of the cathode rays must
be mentioned. A tube was prepared by Crookes (Fig. 4),

Fig. 3-
Fig. 3. In a Geissler tube the current may pass devious paths.

Fig. 4.

Fig. 4. A Crookes tube provided with a window in an aluminum-
shield and fluorescent screen. The cathode rays projected, on the pas-
sage of the current, as a beam upon the screen, appear as a ribbon of light
indicated by the shading. On bringing the pole of a strong magnet
above, the cathode rays are attracted or repelled according to the polar-
ity. The ribbon is bent, the extent of the bending depends upon the
vacuum, strength of the magnet, etc.

4 THE PHENOMENON OF RADIO-ACTIVITY.

whereby a stream of rays could be caused, by means of a
narrow slit in a mica or aluminum partition, to play upon a
screen of some substance which would glow under their influ-
ence. The rays may be deviated by means of a magnet
being attracted or repelled, according to the polarity. An
electric field has the same influence ; these rays are, therefore,
different from light rays. Again, it may be demonstrated
easily that these rays carry considerable energy with them.
By using a concave cathode, the rays which are shot out at
right angles to the surface, may be brought to a focus with the
production of heat at that point. On making the current suffi-
ciently strong, Sir William Crookes was able to fuse platinum-
iridium by this means. Perrin calculated that the amount of
energy produced by the impact of a kilogram of the corpuscles,
assuming them to be particles, woulcTraise to the boiling point
in one second a lake 1,000 hectares (2,500 acres) in area and

5 metres deep.

Crookes' s explanation of the phenomena recounted rests
upon his assumption of material particles of residual gas in
the tube, which being negatively electrified at the surface of
the cathode are repelled by it and driven away with a high
velocity. In support of the electrified radiant matter hypo-
thesis, he devised a variety of tubes for demonstrating the
mechanical action of the particles. Only one tube may be
referred to here,. It is known as the railway tube (Fig. 5).
This tube contains a paddle wheel, whose axle rests upon a
pair of glass rails. By making the proper terminal the

Fig- 5-

Fig. 5. Crookes' "railway tube." The cathode rays coming from one
terminal drive the paddle wheel to the other end of the tube ; by revers-
ing the polarity, without disturbing the level of the tube, it is driven
back.

THP; PHENOMENON OF RADIO-ACTIVITY. 5

cathode, the fly may be driven in either direction. Apparently
in protest to the term ''radiant matter," which implied the
material nature of the particles, the Germans through the
work of Goldstein, Wiedemann, and Lenard, invented the
term, " cathode ray," which is in common use at present.

In 1895 Perrin1 practically proved that the Crookes ray
consists of streams of negatively electrified material particles.
J. J. Thomson2 confirmed these observations in 1897 and later
actually measured their mass, electric charge, and the velo-
city of their movement. For full details one is referred to the
original papers. For our purpose, suffice it to say, he3 learned
that the mass of each of the particles constituting the cathode
rays is only one-thousandth the mass of the hydrogen atom, or
2.3xio"24 milligram* and it has a velocity varying from one to
four-tenths that of light, 2.2-3.6xio9 centimetres per second,
depending upon the degree of exhaustion in the tube.

Thomson, further, showed that the ratio of the mass of a
particle to its electric charge is independent of the nature of
the gas and the electrodes. These particles, as a consequence,
may be said to constitute a kind of matter previously unknown.
The old Newtonian corpuscular theory being so strongly sug-
gested, these particles have been called " corpuscles." They
are constant constituents of all material atoms and molecules.
Many chemists fail to coincide with the views of this eminent
physicist, and few follow him to the extreme suggestion that
these corpuscles constitute4 negative electricity, which implies
a return to the electric single fluid theory of Franklin.

In 1894 Lenard,5 acting upon a suggestion of Hertz,6
replaced a portion of the glass wall of the tube opposite the

1. Compt. Rend. 121, 1130.

2. Phil. Mag. V, 44, 293.

3. Phil. Mag. V, 547 (1899) ; Proc. Roy. Inst. 16,574, (1901).

*It has been calculated that the hydrogen atom weighs 2.3x10-21
milligrams.

4. Harper's Magazine 103, 564, Sept. 1901.

5. Ann. Phys. Chem. 51, 225 ; 56, 255, (1895).

6. Prof. Hertz observed that a very thin metallic film interposed in-
side a Crookes tubes permitted the grass to flouresce under cathodic bom-
bardment. The aluminum foil quite opaque to light, did not prevent
this flourescence of the glass behind it.

6 THE PHENOMENON OF RADIO-ACTIVITY.

cathode with a very thin plate of aluminum (Fig. 6) and thus
led the cathode rays out of doors, as it were, under ordinary
pressure. If the Lenard rays are not a prolongation of the
cathode rays, they are closely identified with them, for they
can be deflected by a magnet, excite luminescence, and they
affect a photographic plate. While the air is a turbid medium
for them, they readily pass through thin sheets of aluminum,
or even copper, and discharge an electroscope enclosed in a
metal box. L,enard explored his rays by using a small lumi-
nescent paper screen covered with a wax -like organic chemi-
cal, pentadecylparatolylketone.

JB
Fig. 6.

Lenard's tube. B is joined to a vacuum pump ; A is anode ; C cath-
ode ; Da thin aluminum window; From S. P. Thompson's "Light;
Visible and Invisible." (Courtesy of the MacMillan Co.)

A year later Rontgen, while investigating cathode rays
as studied by Hertz and Lenard, discovered that something
came from his tube which caused a barium platino-cyanide
screen lying on the table to luminesce strongly. Rontgen's
tube had a greater vacuum, no window (Fig. 7) and was
covered by a shield of black cardboard.1 The cathode rays,
cannot pass through glass. The X-rays, he learned, possess
remarkable penetrative powers, readily passing through paper,
wood, hard rubber, tin and aluminum foil. Silver, copper,
platinum, gold and lead were less and less transparent to them,
a plate of the last named 1.5 centimetres thick being quite
opaque. Rontgen found that his rays affected a photographic

i. Uebereine neue Art von Strahlen (Vorlaufige Mitteilung), Sitzungs
berichte der Wiirzburger physik. medic. Gesellschaft, 1895. Nature 53.
274, (1896); Ann. Phys. Chem. 64, i, 12, 18, 91, 898.

THE PHENOMENON OF RADIO-ACTIVITY. 7

plate and that they differed from light rays, (visible, the ultra-
violet, or infra-red, and any of those we have to consider), in
not being reflected, refracted, or polarized.

Although Rontgen's investigation was very complete,
there was one observation he failed to make, which was noted
by several workers, shortly after his modest announcement,
namely, that Rontgen rays, like the cathode rays, possess the

Fig. 7.

Rontgen's first tube. C. is the cathode. (Courtesy of the MacMil-
lan Co.)

power of ionizing gases, when passed through them ; that is,
dissociating them into ions and rendering them electric
conductors. A charged electroscope (Fig. 8) may be readily
discharged by the surrounding air made a conductor by the
passage of X-rays through it. Ordinary flame will also ionize
air.

The effect upon a photographic plate gave a qualitative
method for studying these rays, while the electrometric proce-
dure presented a means of quantitative comparison.

If the tube be too highly evacuated, no current passes
through at all, a vacuum being a perfect insulator. The expla-
nation of the Rontgen rays at present accepted is that they
are produced without the tube as a result of the bombardment
of the cathode rays within. By the use o£an anti cathode, as
shown in the modern Crookes tube, and by the automatic reg-
ulation of the gas pressure within, the effect of the X-rays
may be accentuated (Fig. 9). A larger surface of the glass
fluoresces and phosphoresces.

In an effort to learn the cause of the photographic effect

THE PHENOMENON OF RADIO-ACTIVITY.

and especially considering if it might be attributed to the
glowing of the walls of the tube, Henry1 found that it could be

Fig. 8.

An electroscope is an instrument which illustrates that like kinds of
electricity repel each other. The illustration shows thin strips of metal
attached to a rod passing through a cork in a bottle. When a charged
body is brought near the knob the leaves within are charged hence di-
verge. Anything which causes the air particles to become better conduc-
tors of electricity than ordinarily, will cause the leaves to collapse. The
rendering of gases, as the air, a better conductor is known as ioniza-
tion. Fig. 8 shows an Aluminum leaf electroscope, covered with a wire
netting and metalic cap, which prevent its discharge by ordinary elec-
tric disturbances. The Rontgen rays discharge it whether charged by
positive or negative electricity.

Fig. 9.

A modern Crookes tube for X-ray work. It is provided with a small
side tube which contains a substance which absorbs or gives up sufficient
gas to produce most penetrative effects.

i. Compt. Rend 122, 384, (1896).

THE PHENOMENON OF RADIO-ACTIVITY. 9

augmented by phosphorescent zinc sulphide and Nieweng-
lowski1 observed that phosphorescing calcium sulphide would
blacken a plate surrounded by light-tight paper. Troost2
made a similar observation with Sidot's blende, and naturally
occurring hexagonal zinc sulphide. H. Becquerel3 (Figs. 10
and n) found that calcium sulphide, the variety which phos-
phoresces blue-greeu to blue, would act strongly upon a photo-
graphic plate through two m.rn. of aluminum foil, even though
it were within a glass tube. W. Arnold4 verified and extended
these observations. The experiences of Madame Curie, Hof-
mann and Z^rban, and ourselves did not accord with these
observations.

As a result of a series of photographic experiments LeBon5
concluded that sunlight generates in all bodies upon which it
falls rays of " black light." The rays are invisible to the
eyes. Their existence is shown by their action on a gelatin-
ized silver bromide plate. Lumiere, Becquerel and d'Arson-
val6 opposed this view and maintained that the black light is a

Fig. 10.

1. Coinpt. Rend. 122, 384, (1896).

2. Compt. Rend. 122, 564, (1896).
.3. Comp. Rend. 122, 559, (1899).

4. Wied. Ann. 61, 316, (1897).

5. Comp. Rend. 122, 188, (1896).

6. Comp. Rend. 122, 500, (1896*.

THE PHENOMENON OF RADIO-ACTIVITY.

Fig. ii.

These two foregoing figures present small glass exhibition tubes
containing various phosphorescing substances resting upon an aluminum
shield, 2 m. m. thick, which is separated from the sensitive film of the
plate by black paper. The second figure is the plate after forty-eight
hours exposure. The "light" from the calcium sulphide and hexagonal
blende did not penetrate the shields. (From Becquerel's paper).

kind of after light. They, also, put forward the idea that
fluorescing substances, as for example the yellowish-green-
glowing glass, are able to send out rays which penetrate dark
bodies similarly to the Rontgen rays.

Physicists have long known that the salts of uranium lum-
inesce most beautifully in the sunlight. Becquerel1 next
directed his attention to the double uranium potassium sul-
phate. This salt was placed on a plate so protected as to pre-
vent the entrance of any sunlight. The whole was then

i. Compt. Rend. 122, pp. 420, 501, 559, 689, 762, 1086, (1896);
I23> 835. Also address before the Roy. Inst., Great Britain, March 7,
(1902).

THE PHENOMENON OF RADIO-ACTIVITY. n

exposed to the sun. On developing, the plate was found to
be darkened. While preparing to repeat the experiment one
day, it became cloudy. The whole apparatus was pliced in a
dark drawer where it remained during several days of inclem-
ent weather. For some unexplained reason the plate was
developed without exposure to the sun at all. To his great
surprise, he found that the plate had been distinctly affected.
Becquerel's eminent father had shown years before that the
phosphorescence of uranium salts persists but a very short time.
Becquerel dissolved the double uranium potassium sulphate
and purified it by recrystallization. The property of phos-
phorescence is not evident in solution. The entire process
was carried out in the dark... He repeated the experiment with
the photographic plate, being careful not to allow any expo-
sure of the apparatus or material to light. (Figs. 12 and 13).
Similar results to those noted above were obtained.

A number of uranium compounds were proved to possess
this property (Fig. 14). The metal itself acted three and a
half times as strong as the original sulphate. Further, while
the light of the alkaline earth sulphides, zinc blende and other
phosphorescing bodies gradually goes out in the dark, Bec-
querel proved that the property of uranium preparations of
giving out rays, which penetrate light tight media, did not di-
minish even when they were kept for months in an abso-
lutely dark place.

Becquerel's statements as to the "uranium rays" were
almost immediately verified and extended by Spies,1 Elster and
Geitel,2 Miethe,3 Kelvin,4 Beattie and de Smolan,5 and Ruther-
ford.6. Later Hofmann and Strauss7 and Crookes8, examined

1. Verb, derphysik. Ges. Berlin 15, 102, (1896).

2. Jahresber. Naturw. Braunschweig, 10, (1897).

3. Intern, photogr. Monatsschrift f . Mediz. 4, 33, (1897'

4. Nature 55, 344, 447, (1896).

5. Phil. Mag. V, 43, 418 and 55, 277, (1897).

6. Phil. Mag. V, 44, 422, (1897) and 47, 109, (1859).

7. Ber. dtsch. Chem. Ges 33, 3126, (1900).

8. Proc. Roy. Soc. 66, 406, (1900).

12 THE PHENOMENON OF RADIO-ACTIVITY.

Fig. 12.

Early Radiograph of an aluminum medal made by Becquerel with
an uranium salt.

Fig. 13.

North Carolina uraninite (gummite) acted through a glass upon the
plate in ninety hours.

THE PHENOMK>ON OF RADIO-ACTIVITY.. 13

Fig. 14.

Radigraph made by J. Collier of Denver with a pitchblende^from
the Wood mine of L,eaven worth gulch, Gilpin county, Colorado. It is
interesting as showing the relative transparency and opaqueness of differ-
ent substances to the radium and uranium radiation. In this case the
plate was not wrapped but enclosed in double light proof box, which was
set in a dark room. Weight of pitchblende 7^ ounces ; distance from
plate, 4 inches ; radiating surface, i^ inches in diamater ; exposure two
weeks. Key to objects — ( i) house finch ; (2) imitation diamond ; (3) real
diamond; (4) cameo; (5) quartz crystal; (6) and (7) fluorspar; (8)
Kauri gum ; (9) tiger ej'e ; (10) turquoise ; (n) thick sheet lead ; (12)
thin sheet lead ; (13) window glass ; (14) centipede ; (15) iceland spar ;
(16) amber ; (17) black rubber.) By courtesy of the Western Miner and
Financier. )

many of the uranium minerals, (pitchblende, uraninite, brog-
gerite, cleveite, samarskite, and autunite, etc.), and found that
they affected the photographic plate in the samejmanner.
(Fig. 15).

It may be recalled that Rontgen rays are able to pene-
trate opaque sheets of metal, black paper, wood, caoutchouc,
and so forth, and that they also have the property of ionizing
gases.1 The discovery showed that the Becquerel rays pos-
sessed the same properties. (Fig. 16).

i. Thomson and Rutherford, Phil. Mag. V, 42, 392, (1896).

14 THE PHENOMENON OF RADIO-ACTIVITY.

It is well known that the components of sunlight are re-
frangible and capable of polarization by means of tourmaline
or Nicol's prisms. Rutherford5 showed that the uranium ray's
possess this property in as limited a degree as the X-rays. This
brilliant physicist, with Soddy,(i showed the complex nature of
the rays.

Those which are designated ,5- Rays have the following
properties :

They are penetrative and affect the photographic plate.

They do not discharge the electroscope hence do not ionize
gases and are but slightly absorbed by them.

When subjected to the influence of the magnetic field,
they are bent like the cathode rays.

Fig. 15-

Carnotite impressions or flashes made by H. H. Buckwalter. Plate
inf double light-proof envelope. Time of exposure, one day. Nos. i
and 2, carnotite concentrates, about seventy-five per cent, uranium from
two per cent. ore. No. 3, very rich carnotite from the vicinity of Natu-
rita, Colorado. (By courtesy of the Western Miner and Financier.

4. Compt. Rend. 124,800, (1897).

5. Phil. Mag. 47, 109, (1899).

6. Proc. Chem. Soc. 18, 121.

THE PHENOMENON OF RADIO-ACTIVITY.

Fig. 16.

Radiograph made with Gilpin county (Colo.) pitchblende, by H. H.
Buckwalter. Plate wrapped in two thicknesses of black paper. Time of
exposure five days. About one-half pound of ore in two samples was
used, separated from objects by a white pine board one inch thick. Dark
circular object, an ordinary glass lens in chamois bag ; square object, an
aluminum box containing washers. Rays at greater angle passing
through greater thickness cause apparent shadow. ( By courtesy of the

Western Miner and Financier. )

A i pH .
The '2- rays act thus :

They have no noticeable effect on the photographic plate.

They are responsible for most of the ionizing effect of the
uranium preparations and are readily absorbed by different
substances.

They are unaffected by the magnet.1

These facts, first established by Rutherford and Soddy,
were subsequently; recognized by Becquerel. (Fig. 17).

This phase of the subject will be reverted to in a later
chapter and we shall put aside its further discussion until
then.

i. This was later found to be incorrect, as will be shown.

THE PHENOMENON OF RADIO-ACTIVITY.

For the present, let us assume the novel fact that energy
comes continuously from uranium and its compounds. This
energy loses nothing in intensity, even on keeping the radiant

Fig. 17.

The figure illustrates the absorption power of the different rays pos-
sessed by the screens of black paper, aluminum o.io m. m., and platinum
0.03 m. m. thick. The rays are deflected by a field about 1,740 C. G. S.
units. The plate is unprotected except for the strips. The differences in
penetration are readily noted. (After Bacquerel.)

material in complete darkness for several years, as shown by
Becquerel, and Elster and Geitel.. To be sure as Rutherford
has shown, this energy is small1 and apparently spontaneous,
unaffected by _ temperature,2 and unchanged in liquid air
(—-i 80° C). What is the cause of this unique physical phe-
nomenon ?

In 1897 Madame Sklodowska Curie of the Ecole Munici-
pale de Physique et de Chimie Industrielle at Paris, began an
investigation of the relative activity of the various salts of
uranium and later minerals bearing that element.3 She meas-
ured the intensity of the radiation by its effect on the conduc-
tivity of the air unit. The apparatus is here described in her
own words :

1. i g. of uranium oxide gives out in a year 0,032 Cal. of energy,
Wied. Ann. Beibl. 24, 1,338, (1900).

2. Rutherford, Phil. Mag. 47, 109, (1899) and Becquerel, Compt.
Rend. 130, 1,584 and 131, 137.

3. Compt. Rend. 126, i, 101, April, 1898. See also her exquisite thesis
presented to the Faculte" des Sciences de Paris, which may te had in
English for a small sum from the Chemical News of London, from which
it has been reprinted.

THE PHENOMENON OF RADIO-ACTIVITY. 17

' ' The method employed consists in measuring the conduc-
tivity acquired by air under the action of radio-active bodies ;
this method possesses the advantage of being rapid and of fur-
nishing figures which are comparable. The apparatus em-
ployed by me for the purpose consists essentially of a plate
condenser, A B (Fig. 18). The active body, finely powdered,
is spread over the plate B, making the air between the plates
a conductor. In order to measure the conductivity, the plate
B is raised to a high potential by connecting it with one pole of
a battery of small accumulators, P, of which the other pole is
connected to earth. The plate A being maintained at the
potential of the earth by the connection C D, an electric cur-
rent is set up between the two plates. The potential of the
plate A is recorded by an electrometer E. If the earth con-
nection be broken at C, the plate A becomes charged, and this
charge causes a deflection of the electrometer. The velocity
of the deflection is proportional to the intensity of the current,
and serves to measure the latter.

' ' But a preferable method of measuring is that of compensa-
ting the charge on plate A, so as to cause no deflection of the
electrometer. The charges in question are extremely weak ;
they may be compensated by means of a quartz electric
balance, Q, one sheath of which is connected to plate A and
the other to earth. The quartz laminae are subjected to a
known tension, produced by placing weights in a plate. The
tension is produced progressively and has the effect of genera-
ting progressively a known quantity of electricity during the
time observed. The operation can be so regulated that, at each
instant there is compensation between the quantity of elec-
tricity that traverses the condenser and that of the opposite
kind furnished by the quartz. In this way the quantity of
electricity passing through the condenser fora given time, z *.,
the intensity of the current, can be measured in absolute units.
The measurement is independent of the sensitiveness of the
electrometer.

"In carrying out a certain number of measurements of this
kind, it is seen that radio-activity is a phenomenon capable of

THE PHENOMENON CF .RADIO-ACTIVITY.

Tcrre

Fig. 18.

Plan of apparatus used by Mme. Curie for measuring the intensity
of radiation from active bodies by their effect on the conductivity of the
air. (From her thesis.)

being measured with a certain accuracy. It varies little with
temperature ; it is scarcely affected by variations in the tem-
perature of the surroundings ; it is not influenced by incandes-
cence of the active substance. The intensity of the current
which traverses the condenser increases with the surface
of the plates. For a given condenser and a given substance the
current increases with the difference of potential between the
plates, with the pressure of the gas which fills the condenser,
and with the distance of the plates, (provided this distance be
not too great in comparison with the diameter). In every case,
for great differences of potential the current attains a limiting
value, which is practically constant. This is the current of sat-
uration, or limiting current. "

A discussion of the laws of conductivity of air and other
gases subjected to the influences of the Rontgen and Bec-
querel rays, cannot be incorporated in a work ef elementary
character, so the reader is referred especially to the investiga-
tions of J. J. Thomson and Rutherford. The mechanics of the
phenomenon appear to be the same in both cases and the
theory agrees well with the observed facts. However, accord-
ing to Townsend, the phenomenon is more complex when the
pressure of the gas is low.

THE PHENOMENON OF RADIO-ACTIVITY. 19

Using the term coined by the brilliant scientist, Madame
Curie, the "radio-activity" of uranium and its compounds
varied with the percentage of the metal present, as shown by
Becquerel, hence the unique property was attributed to that
element. Madame Curie verified the general conclusion, per-
fected methods of measurements and greatly extended the
range of observation with consequent alterations. (Fig. 19).
She measured all the common metals and non-metals, many rare
compounds, and a large number of rocks and minerals. She
found no simple substance other than uranium and thorium
which gave evidence of atomic radio-activity. G. C. Schmidt1
was the first to publish a statement as to the radio-activity of
thorium. A striking fact is to be noted here. Thorium and
uranium were the two elements then known to possess the
highest atomic weights (232 and 240). 2 They frequently occur
in the same minerals.

C' C'

Fig. 19.

Electroscope used by Mme. Curie for qualitative examination of radio-
active substances. The gold leaf I/ when electrified through the termi-
nal at B is repelled from the fixed metal strip I,. Plate P, upon which
the substance to be tested is placed, is connected with the metal case en-
closing the apparatus. Plate P/ is connected with the strips I, and I/.

1. Wied. Ann. 65, 141, (1895).

2. It should be noted that white phosphorus, undergoing oxidation,
according to Black, causes the air to become a conductor. As neither the
red variety nor compounds of phosphorus exhibit this property, it is readily
attributed to chemical action and cannot come into consideration here.

20 THE: PHENOMENON OF RADIO-ACTIVITY.

When the air between the plates becomes ionized a charge passes across-
and I/ falls. By rating the time necessary for collapsing, or by having a
scale at the back and rating the time required for the leaf to pass
through a selected number of divisions, the radio-activity may be ap-
proximately determined, e. £-., that portion which ionizes gases. There
are several forms of apparatus using the same principle. The limits of
this book will not admit of their description, other than to call attention
to Rutherford's variation, namely, the leaves are insulated from the rest
of the apparatus being suspended by means of a sulphur bead. After
charging through the conductor tff, it is swung aside. "The rate of leakage
is thus reduced to a minimum.

The following is a table made by Madame Curie giving
in io"11 amperes the intensity of the current obtained with
metallic uranium and with different minerals.

Uranium •%. . . . s. .. . . . . 2.3

Pitchblende from Johanngeorgenstadt 8.3

Pitchblende from Joachimsthal ... v. .....; 7.0

Pitchblende from Pzibram . . 6.5

Pitchblende from Cornwallis , . . . .1.6

Cleveite 1.4

Autunite : k . 2.7

Chalcolite : . 5.2

O.I

0.7
Various thorites ".-• . . . .1.3

1.4

Orangite 2.0

Monazite 0.5

Xenotime. . - 0.03

Aeschynite o. 7

0.4

Fergusonite (two samples) o. i

Samarskite .....-'... I I

Niobite (two samples) 03

Tantalite 0 02

Carnotite ..... 6.2

All the minerals having radio-activity contained uranium
and thorium. A glance at the table, however, shows the
amazing fact that certain minerals possess a greater intensity
than the metal uranium itself. This is utterly at variance
with what we have already learned, namely, that the radio-

THE PHENOMENON OF RADIO-ACTIVITY. 21

activity is dependent upon the percentage of the metal, ura-
nium or thorium, present.

Afanasjew1 examined fifty- one minerals by their action on
a photographic plate. All the minerals containing uranium
and thorium blackened the plate. Pisani2 made somewhat
similar experiments and raised the question, — Is this astonish-
ing state of affairs due to the small percentage of the oxides of
uranium and thorium, or is it caused by the presence of a new
radio-active body?

To throw light on the subject, Madame Curie prepared
artificial chalcolite, a double copper uranium phosphate, from
pure materials. It showed normal activity, namely two-and-a-
half less than uranium, instead of 5.2 as great. Pisani 's ques-
tion was answered. Madame Curie's inevitable conclusion was.
that pitchblende, chalcolite and autunite contained a small
quantity of a strongly radio-active body, differing from uranium
and thorium, differing from any of the elementary bodies
known.

The difficult problem which confronted this intrepid woman
was the seeking of a new element, each faltering step being
guided by a veritable fairy wand. The glorious outcome of her
researches joined the century most replete with human achieve-
ment to another, which promises even more and greater
marvels.

1. J. Russ. Phys. Chem. Soc. 32, ii, 103 (1900).

2. Bull. Soc. franc. Mineral, 27, 58.

22 THE EXTRACTION OF RADIUM.

CHAPTER II.

THE EXTRACTION OF RADIUM ; ITS PROPERTIES, PHY-
SICAI, AND CHEMICAL.

Pitchblende is an expensive mineral mined mainly in Bohe-
mia for the uranium it contains. It is one of the most com-
plex ores ; containing besides the uranium, iron, calcium, lead,
aluminum, silicon, copper, bismuth, zinc, cobalt, nickel, man-
ganese, antimony, arsenic, vanadium, thallium, columbium,
tantalum, many rare earths, and so forth. In the course of
her search for the cause of the unique properties possessed by
the uranium bearing minerals, Madame Curie1 obtained a very
radio-active substance, resembling bismuth, which she named,
polonium, after her native country. This will be dealt with
later. For this work she received the Gegner prize of 4,000
francs. At this point her husband having joined in the work,
they were assisted by M. Bemont, Director of the Ecole Muni-
cipale.2 Pitchblende, in sufficient amount, being beyond the
purse of the teacher she secured from the Austrian Govern-

1. Compt. Rend. 127, 175. Rapports au Congres International de
Physique, III, 79, Paris (1900).

2. Madame Sklodowska Curie was born in 1867, at Warsaw, Poland,
where she received her early training. In 1891' she went to Paris, con-
tinued her studies at the University and received her "Master's" degree
in Physics and Mathematics. She married Professor Pierre Curie, the
Professor of Physics at the University of Paris, in 1895. The year fol-
lowing she successfully qualified as a candidate for a professorship in a
girl's college. In 1900 she was appointed Professor of Physics in the
State Normal School for Women at Sevres. She received her "Doctor's"
degree recently for the thesis already quoted. The writer knows of no
doctorate dissertation of such scope, elegance, breadth of conception and
importance in its contribution to knowledge.

ITS PROPERTIES, PHYSICAL AND CHEMICAL. 23

ment a ton of the ' ' tailings ' ' or residues of the ores from which
the uranium had been extracted.

To extract the uranium, the process is as follows : The
crude ore is crushed, roasted with sodium carbonate, washed
with warm water and then with sulphuric acid. The solution
contains the uranium. The insoluble residue, "tailings,"
which is rejected, contains most of the bodies of high radio-
activity ; its activity being four and a-half times that of metallic
uranium. Laboratory methods not being easily applied, M.
Debierne organized the treatment in the factory, which was
erected at Ivry without the walls of the city of Paris.

A ton of the residues was worked up and a few decigrams
of a substance resembling barium obtained. This was many
thousand times as active as uranium. Although this substance
showed but slight change in its atomic weight from that of
barium, and no characteristic new lines were to be seen in the
visible spectrum, according to Demarcay, it glowed feebly in
the dark, affected a photographic plate through black paper
and even thin sheets of metal, and ionized gases. These facts
were sufficient to warrant the assumption of the presence of a
new element. It was named radium.1

So far, although Phillips,2 Bolt wood,3 and others have pro-
posed methods for analyzing ores for radium, it has not been
extracted commercially in America. Lockwood, at Buffalo,
has installed a plant for its extraction from carnotite, but as
yet no preparations from that factory have been placed upon
the market.

The importance of the discovery of radium, the minute
percentage in which it is found, the extremely unique proper-
ties possessed by its compounds, the desire for it on the part of
experimenters and even the merely curious, and its possible
utility in medicine have created a radio- mania. The demand

1. Compt. Rend. 127, 1215.

2. American Phil. Academy, April Meeting, (1904). Science, May 6th.

3. Bng. Min. J. May 12, (1904).

Boltwood (Eng. & Min. Jour. 77, 756) tested for the presence of ra-
dium in uranium compounds as follows :

24 THE EXTRACTION OF RADIUM :

has been far in excess of the supply. The prices have almost
tripled. The Austrian Government has forbidden the ship-
ping of uranium ores or tailings without that country. Many
tons of uranium ores have been shipped from the United
States to Europe. The United States Geological Survey in
seeking the locations of all the uranium bearing ores, has
with its usual progressiveness appointed a special expert1 and
issued a letter on the subject. It says :

"The simplest means of detecting radio-activity in a substance is
by use of the photographic plate. The more sensitive the plate the
better. The plate should not be removed from the enclosing black
paper, and a metal object should be laid upon this black paper in a
dark room; upon this should be placed the specimen to be tested.
Instead of the metal object a few small nails may be arranged so as

U-*

"A piece of apparatus (Fig. 21) constructed entirely
of glass was first prepared. This consisted of a bulb (A)
of about 50 cubic centimeters capacity, which was joined
by a short tube to a smaller bulb (B). An accurately
weighed quantity of the very finely powdered mineral
was introduced into the bulb B, and in the bulb C was
placed a sufficient quantity of a suitable acid, its actual
quantity and nature depending on the character of the
particular mineral under investigation. The whole ap-
paratus was then sealed up air-tight at a slightly
diminished pressure and, by tilting, the acid was trans-
ferred to the bulb B, containing the mineral. The
mineral was then completely decomposed by gentle
warming and the apparatus was allowed to stand for
several days to permit the radium emanation, which is
D freed when the radium gaits pass into solution, to diffuse
uniformly through the interior of the apparatus. The
bulb A was then sealed off from the rest of the apparatus,
allowed to stand for two hours, in order that any rapidly
decaying emanations (actinium and thorium) which it
contained might completely decompose, and, after wa-
shing the interior walls with a strong sodium hydroxide
solution to completely remove acid fumes, the air and
radium emanation which it contained was transferred to an air-tight
electroscope, and the rate of the leak measured."

The sensitiveness of the method is extraordinary. Dr. Boltwood was
able to compare the relative quantities of radium in two samples of
pitchblende weighing from .001 to .002 gram. He was able to detect the
presence of .000,000,000,1 gram of radium. It is probably possible to
quantitatively estimate the quantity of radium equal to perhaps i-iooth of
the above.

Fig. 21

i. Dr. Geo. F. Kunz, 40 East 25th St., New York City.

ITS PROPERTIES, PHYSICAL AND CHEMICAL.

' Fig. 2 1 a.

Radium Exhibit of U. S. Geological Survey, Dr. G. F. Kunz, Special
Agent, Louisiana Purchase Exposition, St. Louis, 'Mo., U. S. A. (By
courtesy of the Survey.)

26 THE EXTRACTION OF RADIUM :

to form the initial of the owner and left on the paper-covered plate
below the specimen. The specimen should be left in the dark room
from two to fifteen hours and then developed in the usual manner. If
the specimen has radio-active powers, a photograph of the metal object
or of the nail-formed initial will be produced on the plate exactly as if it
had been exposed to the sun's rays. The test should be made, if
possible, with from half a pound to a pound of the material. The
electrical method is more reliable, but is much more difficult."

M. Jacques Danne,1 Preparator for Mine. Curie, says:
"The extraction of the radium salts from pitchblende and car-
notite takes place in three stages. The first stage consists in
the roasting of the uranium ores, the preliminary roasting with-
out soda, the final roasting with soda and a little saltpetre. The
ores are then treated with sulphuric and a little nitric acid, and
the resulting solution contains the uranium salts, while the
radio-active metals are contained in finely divided form in the
residue as sulphates. The residue is then treated with con-
centrated hydrochloric acid and a part of it goes into solution.
This solution contains the greater part of the elements polonium
and actinium. Polonium is precipitated with sulphuretted
hydrogen and in the filtrate the actinium is thrown down with
ammonia after oxidation. The residue from the treatment with
hydrochloric acid, which contains the radium, is washed with
water and treated with concentrated boiling soda solution, in
order to change the sulphates, which were left undecomposed
by the treatment with hydrochloric acid, into carbonates. The
residue is washed with water and digested with pure hydro-
chloric acid. The solution resulting from this treatment con-
tains radium and a little polonium and actinium. After filtra-
tion the solution is treated with sulphuric acid, which throws
down a mixture of sulphates of radio-active barium, lead, cal-
cium, and a little actinium. One ton of uranium residues
furnished about 10 to 20 kilograms of the mixtures of sul-
phates, the radio-activity of which is 30 to 60 times greater than
that of metallic uranium. The mixture of sulphates is treated
with boiling concentrated soda solution, and the carbonates

i. Genie Civil, Jan. 16 (1904).

ITS PROPERTIES, PHYSICAL AND CHEMICAL. 27

thus obtained are converted into chlorides by hydrochloric acid.
Sulphuretted hydrogen is introduced into the solution, whereby
a small precipitate of active sulphides which still contain the
polonium is formed. The filtrate from this precipitate is then
oxidized with potassium chlorate and precipitated with am-
monia ; the hydrates and oxides thus precipitated still contain
actinium. The filtrate is treated with soda to precipitate the
carbonates of the alkaline earths, this precipitate being then
converted into chlorides and the solution evaporated to dry-
ness. The dry residue is treated with concentrated hydro-
chloric acid, when the radio-active barium chloride and the
radium chloride remain insoluble. This residue of chlorides
is then dissolved in water, the carbonates precipitated by adding
soda, and the precipitate treated with hydrobromic acid in
order to convert the carbonates into bromides. A ton of ma-
terial treated in this way furnishes about 8 to 10 kilograms of
radio-active barium bromide nearly 60 times more radio-active
than metallic uranium. The bromide is now subjected to a
long series of crystallizations,1 dependent upon the fact that the
radium bromide is less soluble in water than the barium bro-
mide. Each crystallization furnishes a product which has a
greater radio-activity than the preceding and this treatment is
kept up until the desired radio-activity is reached."

PHYSICAL PROPERTIES OF RADIUM SALTS.

The element radium has not yet been obtained. Wedekind2
and Marckwald3 have, however, prepared radium amalgams;
the former by electrolysing a halogen compound in the pres-
ence of mercury, and the latter by treatment with sodium amal-
gam. No description of the metal can be given and we do not
know certain of its properties, as the specific gravity, melting
point, etc. Curie says it is a mere matter of obtaining sufficient
of the chloride, when it may be prepared like the alkaline earth

1. As first suggested and done by Giesel.

2. Chem. Zeit. 28, 269 (1904).

3. Berichte, Chem. News, 89, 97.

28 THE: EXTRACTION OF RADIUM :

metals. The difficulty of working with large quantities are very
apparent when we realize that only a few centigrams of fairly
pure material are had from two tons of the ore, and are aware
of certain properties soon to be mentioned.

The chloride, bromide, carbonate, acetate, nitrate, and sul-
phate of radium freshly prepared resemble similar salts of
barium. The nitrates of radium and of barium are about
equally soluble in water. The halides are isomorphous, but
differ slightly in their solubility in water.

Radium salts gradually assume color. Apparently they
undergo alterations through the influence of the rays they emit,
giving out oxygenated chlorine compounds, if the salt be a
chloride. Giesel has shown that a water solution of a radium
salt gives off hydrogen continuously.

The earlier prepared compounds of radium were much
contaminated with barium and gave an atomic weight of 137.5.
barium being 137.35. Successive fractionations gave 146,* I75,2
and finally 225. 8

In order that a new substance may claim a place in the
family of chemical elements, it has been agreed that it must
give a characteristic spark spectrum. A preparation not very
strong was submitted to Demarcay, 4 who found in addition to
the barium lines," a new one in the ultra-violet. With purer
materials that lamented chemist photographed a characteristic
spectrum, which is in general similar to the alkaline earths.
With radium bromide prepared by Giesel, Runge5 and Precht,
Exher and Haschek6 obtained the spark and flame spectra of
the characteristic carmine-red coloration given by the Bunsen
flame. Their work was concerned largely with* the visible

1. Compt. Rend. 129, 20.

2. Compt. Rend. 131, 6.

3 Compt. Rend. 135, 161 (1902).

4- Compt. Rend. 127, 1218 (1898) ; 129, 716 (1899) ; 131, 258 (1900).

5. Astrophys. Journ. i (1900).

6. Sitz. Ak. Wiss. Wien. July (1901).

ITS PROPERTIES, PHYSICAL AND CHEMICAL. 29

spectrum, while Demargay observed the ultra-violet in the main.
Recently Crookes1 made an elaborate and extended study of the
spark spectrum in the ultra-violet region. Runge and Precht2
noted the influence of a magnetic field on the spectrum and that
it was composed of series analogous to calcium, strontium, and
barium. As these series appeared to be connected with the
atomic weights, they calculated that the atomic weight of
radium should be 258. By utilizing the relation between the
spectra of some elements, and the squares of their atomic
weights, Watts3 arrived at the same value given by Mme. Curie.
Although Runge and Precht4 have criticized, perhaps justly,
the method used by Marshall Watts, the value 225 is accepted
for several reasons, one being that that value causes it to fall in
the family of alkaline earths in the periodic system of Mendele-

A radium compound, within a closed glass tube, when
brought near a screen of zinc sulphide, or barium-platino-
cyanide, causes it to glow brightly in a dark room. Photo-
graphic plates, covered with black paper, are at once affected.

Fig. 22.

Radium bromide within a closed glass tube affects the photographic
plate through black paper. Pacini in our laboratory used the radium
tubes as a pencil and traced the above.

i. Sitz. Kgl. Pr. Akad. Wiss Berlin (1904), 417.

2; Phil. Mag. April (1903).

3. Phil. Mag. IV, 5, 203 (1903)-

4- Phil. Mag. IV, 5, 476 (1903)-

30 THE EXTRACTION OF RADIUM :

(Fig. 22.) All the radium compounds, so far obtained, are
luminous in the dark. We do not know whether radium itself
actually gives out luminous rays or whether the luminosity
results from the conversion by the solid substance itself, or the
impurities present, of invisible rays into those which give the
effect of light on the optical organs. The presence of radium
causes certain substances, as Thuringian glass, diamonds, wille-
mite, kunzite, etc., to fluoresce and phosphoresce.

The salts of radium appear to be a source of spontaneous
and continuous evolution of heat. Curie and Laborde1 first
showed that the temperature of an impure radium salt is 1.5° C.

Fig. 23.

Simple method for illustrating the continuous disengagement of
heat by radium. Delicate thermometers (t and t7) in "duplicate are
placed within calorifically isolated vessels (Dewar bulbs), A and A7.
Small tubes of equal size, a and a7, containing molecular weights of, say,
radium and barium chlorides, the latter being inactive, are inserted after
thermic equilibrium has been established. ' (After Curie, see Danne.)

i. Compt. Rend. 136, 673 (1903).

ITS PROPERTIES, PHYSICAL AND CHEMICAL.

Fig. 24.

The quantity of heat given out by a radium salt has been deter-
mined by the apparatus of Dewar and Curie, shown above. A small
thin-walled Dewar bulb, A, containing liquid hydrogen, is immersied in
liquid hydrogen, H'. within a larger thermic insulator, B. Tube H by
means of glass tubing ends underneath the eudiometer, E, over water.
No gas escapes through the exit tube, t, until the tiny glass vessel
containing the radium compound is inserted, after whjch there is a con-
tinuous and regular ebullition. 0.7 gram of radium bromide causes
70 c.c. of hydrogen to be evolved every minute. Freshly prepared salts
disengage relatively smaller amounts of heat.

higher than the surrounding medium (Fig. 23). Later Curie1
found 3° and Giesel 5° C. difference for the bromide. The
former, also, learned that the rate of the emission of heat
depended upon the age of the compound. When the compound
is freshly prepared the emission is small. It increases and
reaches a constant maximum in a month. He also learned that
if the salt be dissolved in water and placed in a sealed tube, that
the difference in condition made no difference in the emission
of heat. By the use of a Bunsen calorimeter, or the other
method shown in the illustration (Fig. 24), Curie and Laborde
learned that one gram of a pure radium salt emits about 100
gram-calories of heat per hour. Runge and Precht2 with others

1. Societe de Physique. (1903).

2. Sitz. Ak. Wiss. Berlin, (1903).

THE EXTRACTION OF RADIUM :

Fig. 25.

Skiagraph of tools made with radium bromide, 300,000 activity.
Eight inches separated the plate and tube. Exposure forty minutes.

PHOTOGRAPHS WITH RADIUM
iAMS 6ROWN&EARL
PrtlUA-

Fig. 26.

Showing penetration of radium rays. A lead bar was placed be-
neath plates of cast iron ^ inch thick (Brown).

ITS PROPERTIES, PHYSICAL AND CHEMICAL.

Fig. 27.

Illustrating the penetrability to radiations of radium of Aluminum
(A), Micro-cover (B), Micro-slide (C), Red flash-glass (D), and a Silver
Quarter (in the center).

confirmed this continuous emission of heat. One gram of
radium emits in a day 2400, or in a year 876,000 gram-calories.
The radiations given out in part penetrate paper, thin
metals, thick metals, glass, mica, etc. This wonderful phenom-
enon has been studied by Strutt,1 the Curies,2 and others. Most
striking experiments, illustrating the penetration of the rays,
are easily performed. (Figs. 25, 26 and 27.) Hammer3 placed
a tube of 7000 activity within a cannon ball, sealed it, and

1. Nature, 39, (1900).

2. Loc., Cit.

3. Radium and other Radio-active Substances, Lecture before the
S. E. E. & Am. El. Ch. Soc., April (1903)-

THE EXTRACTION OF RADIUM :

made a skiagraph. Kunz and the writer1 caused a large tifrany-
ite diamond to glow when radium bromide (300,000 activity)
was protected by covers of glass, gutta-percha, steel tubing,
three sheets of copper, one m.m. of silver and ten c.m. of water.
Radium compounds are the first chemical preparations
^) known to spontaneously charge themselves with electricity.
Placed near electrically charged and isolated bodies, as an elec-
troscope, they discharge them. (Fig. 28.) Thus they ionize
gases, which property serves as a most delicate means of deter-
mining in part the activity quantitatively.2 (Fig. 29.)

HH— ihi

Fig. 28.

This figure illustrates a beautiful experiment of Professor Curie's,
which shews the conductivity of the air under-the influence of radium.
The secondary terminals, P P/, of an induction coil, B, are connected
by wires with two sets of electrodes, M and M', so separated as to offer
two paths for discharging sparks. If a tube of radium be brought near
one- set, while the sparks are passing rapidly between both pairs, the
sparks will cease at the second set as the path offered, where the
radium is present, is much less resistant than the normal air at the
other.

1. Science. N. S. 18, 769, (1903).

2. The term "ionization," as here used, has no reference to the
modern theory of solutions, but to the interpretation given by J. J.
Thomson.

ITS PROPERTIES, PHYSICAL AND CHEMICAL.

Fig. 29.

The apparatus used by the Curies for the determination of
electrical conductivity is described in the words Madame Curie
as follows :

"The two plates of a condenser, P P and P' P' (Fig. 29), are hori-
zontally disposed in a metallic box, B B B B, connected to earth. The
active body, A, placed in a thick metallic box, C C C C, connected with
the plate P' P', acts upon the air of the condenser across a metallic sheet,
T; the rays which pass through the sheet are alone utilized for pro-
ducing the current, the electric field being limited by the sheet. The
distance, A T, of the active body from the sheet may be varied. The
field between the plates is established by means of a battery. By placing
in A upon the active body different screens, and by adjusting the dis-
tance A T; the absorption of rays which travel long or short distances
in the air may be determined."

Attention must be directed at this point to an interesting
phase of the investigation of these radio-active bodies. Coppel1
has determined that by means of the spark spectrum one
may detect i part in 900,000 of barium and I in 100,000,000
of strontium. The principal line of radium in the ultra-
violet may be seen faintly in a preparation 40 times as active
as uranium. By the electrical method, depending upon the
ionization of the air, the presence of radium in a sub-

T. Pogg. Ann. 628, (1870).

36 THE EXTRACTION OF RADIUM :

stance may be detected when it possesses only i/iooo the activ-
ity of uranium. With the most sensitive electrometer 1/10,000
the activity of uranium may be observed. Thus we see that
radio-activity is a detectable property nearly a million times
more sensitive than spectrum analysis, which is at least a
thousand times more sensitive than the most delicate balance.
This should not excite great surprise. Berthelot1 has called
attention to a comparison of the delicacy of detecting radio-
activity and odors, i/ioo billionth of a gram of iodoform is
readily detected by a sensitive nose.

Crookes2 separated from uranium and the writer from
thorium3' a fraction which did not affect the photographic plate.
Rutherford4 showed that this portion, which did not affect the
sensitive gelatine, continued to ionize gases. In short, the
radiations were proved to be complex. (Fig. 30.)

As a result of numerous investigations, by different work-
ers, but mainly Rutherford, the radiations from radium have
been found to consist of three types of rays :

1. Those which are easily absorbed (a- rays) ;

2. Those which are penetrating (/?-rays) ;

3. Those which are very penetrating (y-rays).

Rutherford5 found, both in uranium and thorium, rays
which differed -in their penetrating powers. He designated
them a- and (3- rays. Later the very penetrating rays were
obtained from these two elements and radium and designated
y-rays. The term "ray" is applied to a stream of corpuscles,
such as Newton pictures in his theory of light.

The a- rays correspond to the canal rays of Goldstein
which, according to Wien, consist of positively charged parti-
cles, projected with great velocity. The /8-rays are the same
as the cathode rays, while the y-rays, in .some respects, resem-

1. Compt Rend. 138, 1249.

2. Proc. Roy. Soc., 66, 409. '

3. J. Am. Chem. Soc. 23, 761. (1901).

4. Phila. Mag. (1901). . •
5- Phil. Mag, Jan. (1899).

ITS PROPERTIES, PHYSICAL AND CHEM-ICAL.

Fig. 30. •

Radiograph of a fish obtained by an exposure of 40 minutes with
radium of 300,000 activity. The lack of definition is noticeable, as the
/3-rays were not separated. The lower of the two pictures is a radiograph
of the same fish made by the Roentgen rays.

ble the Rontgen rays. The Rontgen rays result from the ex-
penditure of electric energy within a vacuum tube. They vary
with the conditions, whereas those given out by radio-active
bodies are apparently emitted spontaneously and at a rate not
influenced by any chemical or physical agencies. The velocity
and penetrating powers of the rays from radio-active bodies
appear to be greater than those produced in a vacuum tube.
The method used by Madame Curie for illustrating these rays
is shown in Fig. 32.

The ionization 'effect of the a-, /?- and y-rays is in the
order 10,000 : 100 : i. The penetrating power of the rays

38 THE EXTRACTION OF RADIUM :

is as follows : A sheet of aluminum 0.0005 c-m- thick will cut
off one- half of the a- rays : 0.05 c. m., one-half of the /3-rays,
and 8 c. m., one-half of the y-rays ; or, in short, it will be noted
that ionization and penetration powers bear an approximately
inverse ratio. The making of comparative measurements is
fraught with numerous difficulties, so the figures are only
approximate.

For reasons that will become apparent, these rays will be
considered in the order of their conduct under the influence of
a magnetic or electro-magnetic field.1

THE ft- OR CATHODE RAYS.

Elster and Geitel observed that the conductivity produced
in the air by radium rays was affected by a magnetic field.
Giesel2 demonstrated that the rays deviate under the influence
of an electro-magnet in the same direction and in the same
order of magnitude as the cathode rays. Meyer and von
Schweidler3 verified this later and Becquerel,4 using the photo-
graphic method, demonstrated the magnetic deflection of the
rays. (Fig. 31.) Rutherford5 demonstrated that the rays from
uranium consisted of a- and /3-rays.

P. Curie, by the electrical method, showed that radium
rays consisted of non-deviable and easily absorbed (a- rays)
and penetrating, but deviable by the magnetic field, (/?-rays).
Rutherford and Grier, also using the electrical method, demon-
strated that thorium compounds gave in addition to the a-rays
some penetrating ft- rays, deviable in the magnetic field as in
the case of uranium. The iqnization produced by the a-rays
is large in comparison to that due to the (3-ra.ys.

1. For a complete discussion of the methods of measuring ioniz-
ation of gases the reader is referred to special works like J. J. Thom-
son's "Conduction of Electricity Through Gases," and Rutherford's
"Radio-activity."

2. Wied. Annal. 69, 831, (1899).

3. Phys. Zeit. I, 90, 113, (1899).

4. C. R. 129, 997, 1205, (1899).

5. Phil. Mag., Jan. (1899).

6. Phil. Mag., Sept. (1902).

ITS PROPERTIES, PHYSICAL AND CHEMICAL.

-Fig. 31.

The radium preparation is placed in a small lead cup open above.
The rays are projected like the smoke from a mortar. Under the in-
fluence of a powerful magnet or electro-magnet a portion are attracted,
a portion repelled, and the remainder, being unaffected, continue in a
straight line. (After Curie.) See next figure for a more graphic illus-
tration and the nomenclature of the rays.

Fig. 32.

A graphic illustration of the radiations of radium. The active
preparation (R) is in a lead cup. See description in the text.

40 THE EXTRACTION OF RADIUM :

THE a-RAYS.

The ease with which the p-rays were deviated by the mag-
netic, or electro-magnetic field and their penetration natu-
rally commanded the greater attention at first. A magnetic
field strong enough to produce a marked deviation of the
yS-rays, had little or no effect upon the a- rays. In fact they
were regarded as secondary rays, set up by the /3-rays in the
active matter from which they were produced. It was learned,
as adverted to, that the matter giving rise to the /?-rays could
be separated from uranium, while the intensity of the a-rays
was not affected. Strutt1 and later Crookes* suggested that
the a-rays might consist of positively charged bodies projected
with great velocity. Madame Curie,3 from her study of
polonium, suggested the probability that these rays were bodies
moving very rapidly, but losing their energy when they passed
through matter. Rutherford4 learned, by most careful experi-
mentation with the electrical method, that the a-rays could be
deflected by an intense magnetic field and in the opposite direc-
tion from the cathode rays, and demonstrated that they con-
sisted of positively charged particles.

Becquerel3 confirmed this by the photographic method.
The naked radium preparation was covered with a metallic
screen over a narrow slit. The photographic plate was placed
two c.m. above this slit. The strength of the magnetic field
was great enough to deflect all the /3-rays. The plate was
affected not only immediately opposite the slit, but also on the
side away from the magnetic field. On reversing the field for
equal lengths of time the image, which had been produced by
the a-rays, was observed to be reversed also. " Descoudres6

1. Phil. Trans. 507, (1901).

2. Chem. News 85, 109, (1902).

3. C. R. 130, 76, (1900).

4. Phys. Zeit. 4, 235, (1902).
5 C. R. 136, 199, (1903)-

6. Phys. Zeit. 4, 483, (1903).

ITS PROPERTIES, PHYSICAL AND CHEMICAL. 41

proved that the a-rays of polonium are deviated in the same

manner.

Wien has shown that the velocity of the projection of the
canal rays varies with the gas in the tube and the intensity of
the electric field applied. It is generally about one-tenth of the
velocity of the a-rays from radium. For the a-rays of radium
it has been shown that v = 2.5 X io9 and e/m = 6 X io3,
io4 is the value of e/m for the hydrogen atom liberated in the
electrolysis of water. If the charge of the a particle be the
same as that of the hydrogen atom, the mass of the a particle
is about twice as great as that of the hydrogen, which would
indicate that it consists of either helium or hydrogen. This
phase of the subject will be taken up in the fourth chapter.

The a-rays, coming from different sources, vary in the
amount of their absorption. About ninety-nine per cent, of
the ionization of the air produced by naked radium is due to
the a-rays1. The order of the penetration of the a-emanations
as found is: thorium and radium (excited radiation), thorium,
radium, polonium and uranium. The substances used were :
aluminum, Dutch metal, paper ; air and other gases.

y- OR VERY PENETRATING RAYS.

Villard2 and subsequently Becquerel3 discovered by using
the photographic method these very penetrating rays, which are
non-deviable by a magnetic field. Rutherford, 4 by using the
electroscope of C. T. R. Wilson,5 found that uranium and thor-
ium also gave out y-rays.

T. Rutherford, Phil. Mag., Jan. (1899).

Owens, Phil. Mag. Oct. (1899).

Rutherford and Brookes, Phil. Mag. July, (1902).
2. C. R. 130, 1 1 io, 1178, (1900).
3- C. R. 130, 1154, (1900).
4' Phys. Zeit. pp. 517, (1902).
5. Proc. Roy. Soc. 68, 152, (1901).

42 THE EXTRACTION OF RADIUM :

As a result of the investigations of Benoist,1 Strutt,2 and
others, it is known that the y-rays possess great penetrating
power ; that they are non-deviable in an intense magnetic field ;
that y-rays and /3-rays occur together and in the same propor-
tion ; that thev seem to be absorbed in a similar way to the

33-

The figure illustrates the method for obtaining sharp radiographs
at variable distances, with salts of radium. The ordinary radiographs
made by radium are poorly defined on account of the diffusion of the
/3-rays. The tf-rays are absorbed by the container. The /?-rays are got
rid of through the influence of a powerful electro-magnet. The radium
compound, R, therefore acts like a minute but powerful Crookes tube
evolving Roentgen rays, which produce a skiagraph of T:he object, O,
on the plate, P protected by black paper. The y-rays from a small
amount of radium may be caused to radiograph at variable distances,
a meter or more, the time of exposure being much greater the farther
apart are the plate and the source of energy.

1. C. R. 132, 545, (1901).

2. Proc. Roy. Soc. 72, 208, (1903).

ITS PROPERTIES, PHYSICAL AND CHEMICAL. 43

cathode and /3-rays ; and that active products, giving off a- rays
and not /3-rays, do not produce y-rays. They appear to be
very similar to the Rontgen rays that are produced in very
"hard" tubes.

Radium preparations brought near other substances pos-
sess the power of inducing a secondary activity which dimin-
ishes at various rates. They do not appear to lose weight.
Such conduct apparently questions the fundamental laws of
physics and chemistry, namely the conservation of mass and
energy. This will be dealt with in the fourth chapter.

Black1 has shown that the electric resistance of selenium
is diminished under the influence of radium rays. The action,
though slower than in case of Rontgen rays, is of the same
order of magnitude, as shown by Perrin. Van Aubel2 has also
shown that the electric conductivity of selenium is similarly
affected in the neighborhood of hydrogen and oil of turpentine.
Paillat3 has called attention to the influence the radium rays
have upon the electrical resistance of bismuth.

Gases subjected to the influence of radio-active substances,
according to de Hemptinne,4 became luminous under electric
discharges or higher pressures than normal conditions. There
is a similarity, although a difference, between the Rontgen and
Becquerel rays, the red-violet color of the gas in the former
becoming yellowish-green under the influence of radio-active
bodies.

CHEMICAL ACTION OF RADIUM COMPOUNDS.

Radium preparations produce colors in glass, porcelain,
rock salt, sylvite, etc. They have a destructive action on the
skin ( See Chapter V ) . Becquerel 5 converted yellow phos-
sphorus into the red variety through the influence of the /3-rays,

1. C. R. 132, 15- -

2. C. R. 136, 929.

3. C. R. 138, 139-

A. C. R. 133, 93-1, (1901)-
5. C. R. 133, 709, (1901)-

44 THE EXTRACTION OF RADIUM :

He, also, learned that mercuric chloride is reduced by oxalic
acid when the mixed solutions are left in the dark with a radium
tube. The germinating power of seeds is destroyed by an
ante-planting exposure to the radiations.

Radium converts oxygen into ozone, 'apparently through
the influence of the a- and j3- and not the luminous rays.

Berthelot2in making a comparative study of specific chemi-
cal reactions caused by light, an electric current and radium,
learned that, under the influence of the last named, iodic acid
was decomposed, yielding free iodine. This did not occur when
the radium was covered with black paper. Pure nitric acid
was discolored at the end of a two days' exposure. These re-
actions are endo- thermic. Light caused the decomposition of
carbon disulphide. Acetylene is readily polymerized by an
electric current. Radium brought about neither of these
exothermic reactions. Lead glass was turned black, manganese
glass violet, hence the radiations were supposed to cause a re-
duction and oxidation simultaneously. However, later Ackroyd3
showed that the color changes, as orange for sodium chloride,
violet for potassium chloride, etc., produced by the y-rays, cor-
responded to thermal effects in other bodies and are physical.

Mercurous sulphate, which darkens under the influence
of ordinary light, especially the ultra-violet rays, is similarly
affected by radium compounds.4 The effect on the E. M. F.
of a Clark cell is negligible, however.

Sudborough5 has shown that certain labile stereoisomer-
ides, as allo-cinnamic, a- and /3-bromo-allo-cinnamic acids are
transformed into stable compounds more readily under the in-

1. Curies, C. R. 129, 823, (1899).

2. Compt. Rend. 133, 18. Ann. Chem. Phys. (7), 25, 458, (1902).

3. "The Action of Radium Rays on the Halides of the Alkali Metals
and Analogous Effects produced by Heat." Proc. Chem. S. 20, 108,
(1904).

4. Skinner, "Action of Radium Rays on Mercurous Salts," Proc.
Camb. Phil. Soc. 12, 260, (1904).

5. Proc. C. S. 20, 1 66, (1904).

ITS PROPERTIES, PHYSICAL AND CHEMICAL. 45

fluence of light than by prolonged exposure to radium radia-
tions.

Orloff1 found that radio-active protuberances grew upon
an aluminum plate exposed for three months above radium
bromide in an ebonite capsule. He explained the phenomenon
by the formation of a 'stable alloy with the accumulated ma-
terial particles given off by the radium preparations.

Hardy and Willcockz found that a solution of iodoform in
chloroform turned deep purple by resting the containing vessel
on a sheet of mica covering radium bromide. The liberation
of iodine from solutions of iodoform has been found to require
oxygen and some form of radiant energy. The action was
found to be due mainly to the /3-rays, although the y-rays pro-
duced the same effect. Rontgen rays produce a similar colora-
tion.

Hardy exposed two solutions of globulin from ox-serum
to the action of naked radium bromide. One solution was ren-,
dered electro-positive, by adding acetic acid; the other nega-
tive, by ammonia. The opalescence of the electro-positive prep-
aration rapidly diminished, showing a more complete solution ;
while the electro-negative rapidly turned to a jelly and became
opaque. This coagulation of globulin was found to be due
to the a- rays alone.

This unique substance, it has thus been seen, possesses
properties that are most amazing. Although the trail has been
followed close by many drawn to a contemplation of the won-
der, it is safe to say that we perhaps are only on the threshold
of a full knowledge of this marvel.

1. Russ. Phys. Chem. Soc., April (1903).

2. Proc. Roy. Soc. 72, 200, (1903) ; Zeit. Phys. Chem. 47, 347.

46 OTHER RADIO-ACTIVE BODIES AND

CHAPTER III.

OTHER RADIO-ACTIVE BODIES AND THE SOURCES
OF RADIO-ACTIVITY.

Uranium.

Becquerel1 in his early studies of the invisible radiations
emitted by salts of uranium attributed the darkening of the
photographic plate to invisible phosphorescence. It did not
seem to have any intimate association with visible phosphores-
cence or fluorescence. The sesqui-salts are fluorescent, while
the uranous or green salts are not, yet the radiations from the
latter were as intense as the former.

He2 found that all uranium salts, as well as the metal, gave
off invisible rays which penetrate gold, platinum and copper,
black paper and affect a photographic plate.

Becquerel3 also learned that the radiations from uranium
and its compounds showed no appreciable variation after three
years. The rays were absorbed in proportion to the thickness
of any material they passed through. All the uranium rays
deviate under the influence of an electro-magnet. They resem-
ble Rontgen rays more than ordinary light. The radiating sub-
stances seem to be analogous to ordinary phosphorescent ma-
terials, but to retain relatively a very much greater reserve of
energy.

Becquerel,4 in an effort to concentrate the active body in
uranium, treated its salts with barium chloride, and subse-
quently precipitated the latter by sulphuric acid. The precipi-

1. Compt. Rend. 122, 689 and 762.

2. Compt. Rend. 122, 1086.

3. Compt. Rend. 128, 771 (1899).

4. Compt. Rend. 131, 137 (1900).

THE SOURCES OF RADIO-ACTIVITY. 47

tate carried with it a radio-active substance emitting rays
deviated by a* magnetic field. On repeating the operation
eighteen times it was learned that the purified uranium pos-
sessed only one-sixth its original ability of ionizing air. Its
rays passed more readily through glass than aluminum, whereas
the converse was true for the original salt.

Crookes1 learned that pure uranium nitrate fractioned with
ether gave an inactive product (to the photographic plate),
soluble in ether, while the activity became concentrated in the
insoluble portion. He designated the active substance, pro-
visionally, Ur-X. It differs from polonium, whose emanations
do not pass through glass, aluminum or lead. It differs from
radium in forming a readily soluble sulphate.

Becquerel2 supposed uranium to contain a highly active
body, probably actinium, as a strongly radiating body could be
concentrated by adding a small portion of a soluble barium salt
and precipitating with sulphuric acid. Yet the extreme prod-
ucts of a long series of fractionations of uranium nitrate by
deBoisbaudran showed the same radio-activity, measured by
the photographic and electrical discharge methods.

Becquerel3 found that the temperature of liquid air, reduced
the discharging power of uranium, determined by a very deli-
cate electroscope, to about one-half of that noted at 25° C.
Crystals of uranium nitrate plunged into liquid air or hydrogen
became spontaneously luminous.

He4 furthermore proved that the radio-activity of uranium
was not constant, as Giesel had previously noted.

Soddy3 repeated the work of Crookes. He directed atten-
tion to the fact, that by the photographic method, when the rays

1. Proc. Roy. Soc. 66, 409 (1900).

2. Compt. Rend, 130, 1583 (1900).

3. Compt. Rend. 133, 4 (1901).

4. Compt. Rend, 133, Dec. 9 (1901).

5. Chem. News 86, 199 (1902).

48 OTHER RADIO-ACTIVE BODIES AND

are made to pass through cardboard or glass before reaching
the sensitive film, only the y- radiation will be measured, there-
fore the a-radiation was left intact.

Rutherford1 showed that the radiation from uranium was
complex, the (3- radiation being far more penetrating in charac-
ter than the a-radiation. The difficulty of making an accurate
determination is due to the small conductivity produced by the
/3-radiation in the gas, as compared to that due to the a-radia-
tion.

Thorium.

In 1898 G. C. Schmidt'2 and Madame Curie' independently
noted the radio-activity of thorium obtained from Bohemian
pitchblende. Not long after the announcement of the Becque-
rel4 rays, Crookes,5 as noted above, showed that by fractioning
uranium nitrate with efher, compounds could be obtained which
did not affect the photo-graphic plate. This indicated the sep-
aration of a new substance (Uranium X) and that radio- activ-
ity was not an inherent property of the element uranium, as
maintained by Madame Curie.0

Soddy and Rutherford7 demonstrated that only material
carrying the /8-rays was thus separated and that the inactive
uranium (so called because it does not affect the photographic
plate) still gives off a- rays, which ionize gases and may be
detected by the ejectrical method. Crookes, in the same paper,
reported a few preliminary experiments on thorium compounds
and suggested "the possibility of separating thorium from its
radio-active substance."

Hofmann and Zerban8 found that the activity of thorium
could be fractioned away. The activity is increased in that

1. Phil. Mag. Jan., 1897.

2. Wied. Ann. 65, 141.

3. Madame Curie's Thesis, Faculte des Sciences de Paris (1903).

4. Compt. Rend. 122, 420, 501, 559, 689, 762', 1086 (1896).

5. Proc. Roy. Soc. 66, 406 (1900).

6. Compt. Rend, 127, 175.

7. Proc. Chem. Soc. 18, 121.

8. Ber. d. chem. Ges. 35, 531 (1902).

THE SOURCES OF RADIO-ACTIVITY. 49

portion most readily precipitated by potassium sulphate, chro-
mate, hydrogen dioxide, and sodium thio-sulphate. With am-
monium carbonate the more active portion passes into solution
They also examined a number of minerals from which thorium
is obtained and proved the presence therein of uranium The
thorium oxides from all of these were radio-active. Norwegian
gadolmite, orthite and yttrotitanite free from uranium gave
a thorium oxide which neither affected the electroscope nor the
photographic plate.1

Fig- 3-1-

This illustration shows on the left the action of a strong radio-
active thorium preparation acting through i m.m. of glass upon a plate ;
on the right the same preparation was placed, a half year later, black
paper only protecting the powder from the plate. The loss of the in-
duced (?) activity, or at least that portion affecting a silver-bromide
gelatine preparation is very noticeable. The exposure was for twenty-
four hours in both cases (After Zerban.)

I. Ber. d. Chem. Ges 35, 533 and 145 (1902).

50 OTHER RADIO-ACTIVE BODIES AND

The work of Hofmann and Zerban touching the primary
activity of thorium being questioned by Barker,1 was upheld
by the junior author who detected the presence of uranium in
monazite.

The elegant researches of Rutherford and Soddy2 proved
that there can be no doubt of the existence of a novel highly
radio-active substance with thorium (thorium X), as it is
usually extracted from minerals without consideration of their
chemical composition. Hofmann and Zerban strenuously direct
attention to this last fact. Such prepared so-called pure salts
of thorium contain a radio-active constituent, which may be
concentrated chemically by precipitation with ammonia (the
filtrate carries thorium X)3 and washing the oxide with acid or
even water. The residues obtained by evaporation of the am-
moniacal solution in the first case are a thousand times as active
as the original and "are free from thorium, or, at most, contain
only the merest traces, and when redissolved in nitric acid do
not appear to give any characteristic reaction." The residue
from the water washings became 1,800 times as active, and after
conversion into sulphate, Rutherford and Soddy state, "No
other substance than thorium could be detected by chemical
analysis, although, of course, the quantity was too small for a
minute examination"4 (See Emanium).

Giesel' said the radio-activity of thorium could not be due
to actinium.

When we Consider that barium chloride containing radium
may be precipitated by sulphuric acid or silver nitrate and the
filtrate or precipitate obtained thereby, supposedly containing
none of that remarkable body, is still radio-active,15 we can easily

1. "The Radioactivity of Thorium Minerals," Am. J. Sci. 16, 164

(1903)-

2. Proc. Chem. Soc. (London), 18, 2 (1902).

3. Rutherford and Soddy; Phil. Mag. (1902), p. 370.

4. Italics theirs.

5. Berichte 34, 3776.

6. See the works of the Curies, Giesel, Elster and Geitel, Marck-
wald and others.

THE SOURCES OF RADIO-ACTIVITY. 51

understand how in a mineral or salt a radio-active body, perhaps
resembling one of the constituents, clings to various compon-
ents throughout many chemical manipulations. It having been
suggested that uranium might owe its radio-activity to the
presence of small amounts of polonium or radium, Mme. Curie1
states that such could not be true, and adds in another paper,2
"the property of emitting rays, * * * * which act on photo-
graphic plates, is a specific property of uranium and thorium."
''The physical condition of the metal seems to be of an alto-
gether secondary importance." "Uranium and thorium alone
are practically active."

The power possessed by thorium, as usually prepared, of
inducing activity, reported by Rutherford and his co-workers,3
is most interesting. The brilliant French woman states con-
cerning uranium:4 "I have never found any marked difference
between the relative activities of the same compounds." By
analogy one may consistently assume the same for thorium.
The author has obtained similar compounds of thorium frac-
tions which do differ in their radio-activity, in some cases one-
being three times as great.

Metzger5 has published an interesting and novel method
for separating thorium from cerium, lanthanum, and didymium,
depending upon its precipitation from a neutral solution by a
forty per cent, alcoholic solution of fumaric acid. The writer
.and Lemly6 have verified these observations as far as ordinary
analytical methods are concerned. Applying it to the accepted
chemically pure thorium, however, we obtained a filtrate con-
taining less than 0.5 per cent, of the original, which, on evapora-
tion and ignition, gave a grayish oxide possessing such marked

1. Revue generate des Sciences, January, 1899; M. and Mme. Curie:
Compt. Rend., 127, 175.

2. M. and Mme. Curie and M. Bemont : Compt. Rend. 127, 1215.

3. Loc. cit.

4. Ibid.

5. Journ. Amer. Chem. Soc. 24, 901.

6. Unpublished work.

52 OTHER RADIO-ACTIVE BODIES AND

radio-activity by the electrical method that Dr. Pegram stated,
that it acted as if "salted with radium." This decayed with fair
rapidity, from 42 to 12.4 in eight days, to 3.3 in nine days more
(uranium being taken as the standard unit). After thirty-two
days more it gave 3 and was practically constant. The corre-
sponding values obtained for the thorium precipitate, which
constituted virtually the whole, were 0.63, 0.92 and i. Truly
but one interpretation of these results may logically be had,
namely, the existence of a radio-active body with thorium, which
is different from it. Crookes has sounded a timely warning
against depending upon the photographic method for deter-
mining the radio-activity, so we have been guided mainly by
the electrical method. Although by no means comparable to
the other procedure, yet most interesting observations may be
had by the photographic method. It has been used to secure
very rough quantitative results. It aids one much in learning
of the ft- activity. The a- rays are the most important factor
in the ionization of gases, upon which depends the electrical
method. Persistent differences, in radio-activity of the prepara-
tions had by different chemical methods, have been noted and
the same method of preparation has given persistent differ-
ences in radio-activity measured by the same and different
methods.

Radio-active thorium obtained from monazite has been
resolved by the writer into at least two and most likely three
different constituents.1 All these are radio-active, but of differ-
ent strength. Recently the writer and Zerban have obtained a
thorium preparation from an inactive South American mineral,
which is free from any activity whatever.

Ramsay reported the extraction of a very active body like
thorium from a new Ceylon mineral. This cubical mineral is
very radio-active and gives out large amounts of helium, which
Tyrer has collected in twenty-five liter lots. The constituent,

i. Thorium; Carolinium, Berzelium. Journ. Amer. Chem. Soc. 26,
922 (1904).

THE: SOURCES OF RADIO-ACTIVITY. e-,

resembles thorium and shows an atomic weight of 240 in the
impure form and may contain the carolinium of Baskerville.

Polonium.

When pitchblende was dissolved in acid, and sulphuretted
hydrogen added, the sulphides obtained were very active. On
purification, a substance similar to bismuth was obtained and
Madame Curie1 named this first radio-active element Polonium,
after her native country.

Polonium may be partially separated by any one of the
following three methods: First, the active sulphide, being
more volatile than bismuth, may be sublimed in a tube between
250° and 300° C. and the active body is obtained as a black sub-
stance. Second, the active sulphide is less soluble than the
inactive one, hence partial separation may be obtained by pre-
cipitation with sulphuretted hydrogen in a hydrochloric acid
solution. Third, polonium nitrate hydrolyses more easily than
bismuth nitrate, therefore the active body is precipitated by
adding water to the nitric acid solution.

By using the last mentioned method, which is very slow
and tedious, Madame Curie2 obtained a small quantity of ma-
terial extremely active compared with uranium. Only the bis-
muth lines were observed in the spectrum, as reported by
Demargay, Runge and Exner. Crookes3 observed one new line
in the ultra-violet and Berndt4 saw a large number of new lines
in the same region when he used a polonium of 300 activity.

Polonium apparently gives radiations that are very easily
absorbable. Giesel5 called attention to the fact that the penetra-
ting power of the polonium radiation is much less than that of
radium rays, consequently the shadow produced by an object

1. C. R. 127, 175 (1898).

2. See her thesis.

3. Proc. Roy. Soc., May (1900).

4- Phys. Zeit. 2, 180 (1900).

5- Ann. Phys. Chem. (1899), n, 69-

54 OTHER RADIO-ACTIVE BODIES AND

is much sharper and deeper with the former than with the
latter (Fig. 35).

Becquerel examined samples of polonium nitrate nearly
as active as the radium salts then had. The radiations appeared
to be unaffected by the magnetic field, thus differing from those
of radium.

The activity is not constant, but diminishes regularly ac-
cording to the time. In eleven months Madame Curie found
that polonium lost one-half of its original activity. This fact
has caused many to view polonium not as a new element, but
merely as active bismuth, for it is well known that inactive
elements in the presence of active ones acquire activity. There
is another view of the matter, however; namely, the supposed
presence of a very small quantity of some intensely active mat-
ter. Polonium is therefore not as yet accepted as an element.

Fig- 35-

According to Becquerel, polonium rays do not pass through a thin
film of black paper, forming a small cylinder enclosed with aluminum or
mica, upon the bottom of which rests the powder; the radium rays
readily transverse the envelope. The figure illustrates strikingly the
difference in the rays.

THE SOURCES OF RADIO-ACTIVITY. 55

Marckwald,1 entering the discussion as to the -elementary
character of polonium, reported the rinding of a substance in
pitchblende similar to polonium, but whose activity did not
decay with time. A rod of bismuth dipped into the active solu-
tion obtained from the uranium residues quickly acquired a
black, intensely active deposit. (See radio-tellurium.)

Giesel2 confirmed Marckwald's statement that bismuth im-
mersed in a solution of Curie's polonium, acquired the property
of emitting a- rays. Bismuth, platinum, and palladium may be
rendered highly active by immersion in a solution of radium
salts. After the metal is carefully washed with hydrochloric acid
and water, to remove traces of radium, it still emits the a- rays
strongly. Bismuth becomes mucR more active than the other
two elements, consequently Giesel insisted that polonium is
nothing more than bismuth rendered active by contact with
radium salts. This German scientist also learned that after
bismuth remained in a one per cent, radium salt solution for
several days and was then removed and washed with hydro-
chloric acid and water, it showed intense a- radiation, but no
^-radiation. The small quantities of bismuth and platinum
metals that were dissolved in this experiment were precipitated
with hydrogen sulphide. These sulphides were found to emit
the /3-rays. This may be ascribed to the adhering radium salts.
One of the methods for distinguishing the different rays de-
pends upon the observations of Crookes, Elster and Geitel ;
namely, the scintillations produced by the a- rays, whereas the
/?- radiations produce only uniform illumination of the screens.

The Curies,3 from various observations, concluded that the
radio-activity of uranium, thorium, radium, and probably actin-
ium, is the same and does not vary with time when the radio-
active substance is brought into the same chemical and physical
state. If by any particular treatment the substance loses any
of its activity, it regains it in the course of time. Polonium acts
differently.

1. Berichte 35, 2285 (1902) and elsewhere.

2. Berichte 36, 23, 68 (1903)-

3. Compt. Rend. 134, 85 (1902).

56 OTHER RADIO-ACTIVE BODIES AND

Actinium.

Debierne,1 who directed the factory work of the Curies,
obtained from pitchblende an active substance which was pre-
cipitated in the iron group and which appeared to be very
closely allied to titanium and thorium, especially the latter. He
named it Actinium. This substance has never been obtained in
sufficient purity to give a characteristic spectrum. It should be
mentioned, however, that the spectrum of thorium itself is
extremely complicated. Four methods were used by Debierne
for partial separation, as follows :

First. The active matter accumulated in the precipitate pro-
duced by sodium thio-sulphate in hot solutions, made slightly
acid with hydrochloric acid.

Second. Titanium was separated by the action of hydro-
fluoric acid upon the suspended hydrates in water. The actin-
ium accumulated in the undissolved portion.

Third. When a neutral nitrate solution was precipitated by
hydrogen peroxide, the active body accumulated in the precipi-
tate.

Fourth. If the sulphates were treated with a soluble barium
salt, the barium sulphate which was formed carried down the
actinium matter. This was separated from the barium after
conversion into th£ chloride, by cooking with sodium carbonate,
filtering, dissolving the precipitate in hydrochloric acid and
adding ammonia.

The original material was free from uranium. After sep-
arating the other known radio-active bodies, radium and polon-
ium, a preparation 5,000 times as active as uranium was
obtained.

Actinium renders gases capable of discharging electrified
bodies, excites fluorescence in a barium-platino cyanide screen
and affects photographic plates (Fig. 36). It is said to differ
from radium in not being spontaneously luminous.

i. C. R. 129, 593 (1899); 130, 906 (1900).

THE SOURCES OF RADIO-ACTIVITY.

D C

Fig. 36.

The figure illustrates the action of radium bromide 300,000, "uranies"
strong, (A and B) and actinium oxide, 10,000 uranies, (C and D) on
photographic plates through the thin glass of the containers. A and C
were exposed to the plates, covered with black paper, for two hours.
Practically no action on the sensitive film was observed for the actinium.
B and D were allowed to remain fourteen hours. A marked difference
is observed in the character of the radio-activity of the two substances.
That of radium is more complex. The term "uranies" was coined by
Roberts to mean the standard in terms of the activity of metallic uran-
ium (unity).

Actinium gives out easily absorbable and penetrating, devi-
able rays, like cathode streams, and a radio-active emanation,
which loses its activity in a few seconds. While it resembles
the thorium emanation, it differs from it in the rate of decay.

58 OTHER RADIO-ACTIVE BODIES AND

The thorium emanation loses one-half of its activity in one
minute.1

The deviation2 was found to correspond to positively
charged bodies moving with a high velocity. The induced
radio-activity was shown by Debierne in the following manner :
Two plates were placed at an angle over a tube containing an
actinium salt. The ions are contained almost exclusively in
the tube above the salt, but the plates become radio-active. This
can only be accounted for by a secondary radiation proceeding
from each ion, as the radiation is deviated in a magnetic or
electric field as has been established.

No atomic weight has been obtained for actinium. Hof-
mann and Zerban3 obtained the equivalent 63.32 or atomic mass
value of 253.28 (tetrad.) for a preparation of 2,000 activity.

Radio- Active Lead.

Elster and Geitel4 obtained a very active lead sulphate
from pitchblende. They were able to extract from this an
inactive lead sulphate. Therefore, they attributed its activity
to the presence of more or less radium.

GieseP obtained a small sample of radio-active lead sul-
phate from uranium residues which, when wrapped in black
paper, did not produce any effect upon the photographic plate.
When surrounded by transparent paper, however, the plate
was affected. He, therefore, attributed the action to that of
light rays given off by the phosphorescent substance. He calls
attention to the fact that lead might contain a very minute
amount of radium, much less than one is able to detect by
chemical means, and still be radio-active.

Hofmann and Strauss6 obtained a lead sulphate from
pitchblende, uranium, mica,broggerite, cleveite, and samarskite.

1. C. R. 136, 446 (1903).

2. Compt. Rend. 136, 671 (1903).

3- Berichte 36, 3093 (1903)-

4- Wied. Anal. 69, 83 (1899).

5- Berichte 34, 3772 (1901).

6- Berichte 33, 3126 (1900).

THE SOURCES OF RADIO-ACTIVITY. 59

which were radio-active. It contained no trace of bismuth,
barium, (which precluded the presence of polonium and ra-
dium), titanium, thorium, or uranium. The sulphate was insolu-
ble in dilute sulphuric acid, but easily soluble in aminoniacal
tartrate. The chloride showed diminished radio-activity when
crystallized from hot water, whereas the mother liquor gave
crystals with increased activity.

These same workers1 purified their active lead sulphate
by converting it into the carbonate and then into the chloride.
They were able to fraction the sulphate into more active prep-
arations, which gave a blue phosphorescence when exposed to
the cathode rays. The spark spectrum gave a characteristic
line in the violet.

Potassium iodide converts the sulphate into a mass of yel-
low crystals, which dissolve in warm dilute sulphuric acid and
separate again on heating. From a determination of the per-
centage of the sulphur tetroxide, it was learned that the metal
present was both bivalent and quadrivalent. The radio-activ-
ity of the sulphate diminished on keeping, but was entirely
restored on exposure to the cathode rays. The atomic weight
of 260 has been assigned to radio-active lead. It resembles
ordinary lead in most of its characteristics, except that the
sulphate is strongly phosphorescent.

They2 also isolated from broggerite two elements ( ?) of
the atomic weights 100.92 and 171.96. The former gives a
yellow sulphate and has little influence on the radio-activity
of the lead. The strong radio-activity of the other is lost when
converted into the sulphide. This is obtained again when the
sulphide is reconverted into the sulphate.

The chromate3 of the radio-active lead is not decomposed
on repeated warming with dilute sulphuric acid, which distin-
guishes it from ordinary lead chromate. The sulphate acts

1. Berichte 34, 8 (1901).

2. Berichte 34, 907 (1901).
3- Berichte 34, 3O33 (1901).

60 OTHER RADIO-ACTIVE BODIES AND

upon a photographic plate through aluminum and glass. All
of the radio-activity is effective in discharging the electroscope.

Hofmann with Wolfl1 found that the radio-active lead could
be concentrated by dissolving the lead sulphide in aqueous
sodium thio-sulphate. On keeping for several days an active
black sulphide separated out. Unlike polonium, this radio-
active lead acted on a photographic plate with great rapidity
through a sheet of gutta percha.

Giesel2 found that the radio-activity of the radio-active
lead which he obtained diminished with time, whereas Hof-
mann's preparations preserved their activity.

Winkler has questioned the method of the determination
of the atomic weight, but Hofmann has apparently substan-
tiated his claims. (See Chapter V.)

Radio -Tellurium.

Marckwald3 obtained 1.5 grams of radio-active tellurium
from six kilograms of bismuth oxychloride which was extracted
from 2,000 kilograms of pitchblende. This contained only
about one per cent, of the radio-active constituent. The whole
was converted into the chloride and precipitated by hydrazine.
The filtrate was concentrated and heated on a water bath with
a drop of stannous chloride. In this way four milligrams of
a dark colored -precipitate were obtained. This radio-active
substance dissolves in cold nitric acid and may be converted into
a soluble chloride. Upon the immersion of a copper, tin, or
antimony plate in the solution, the active substance is deposited
in a fine state of subdivision, o.oi milligram separated on the
copper plate. Four square centimetres of this plate illuminated
a zinc-blende screen so that it was visible to several hundred
people.

The polonium of. Madame Curie behaves quite differently
from radio-tellurium, in that its nitric acid solution gives with

i. Berichte 35, 1453 (1902).
2 Berichte 34, 3775 (1901).
3. Berichte 36, 2662 (1903).

THE SOURCES OF RADIO-ACTIVITY. 61

water a yellow to brown precipitate, soluble in acids. The
polonium of Giesel is also quite different.

Bismuth dipped into a solution containing radium becomes
radio-active, but its activity is not comparable with that of
radio-tellurium. The solution is not at all exhausted.

Tellurium precipitated by stannous chloride from a solu-
tion of tellurous acid, containing radium chloride, although
somewhat active, gives when converted into the chloride, a
liquid which fails to render active a copper strip immersed in
it. Therefore, the induced activity is doubtless different from
the activity of radio-tellurium.

Marckwald,1 who entered a discussion on the complicated
question of the nature of polonium, secured from pitchblende
a' substance resembling tellurium, which is active, but whose
activity does not decay with time. The method of separation
depended upon the insertion of a rod of bismuth into the bis-
muth chloride solution, obtained from the uranium residues.
The black deposit which coats the bismuth is very active. Hav-
ing obtained .6 gram of the substance, he proved that its activ-
ity did not decay within nine months.

The chloride was electrolysed for three days ; a bismuth
cathode and carbon anode were used. The solution became
inactive. The deposited metal is much more radio-active than
the original substance. The deposit, which contains a little
chloride, was sublimed from the bismuth terminal. The metal-
lic bead obtained was dissolved in nitric acid. The solution gave
the reactions of bismuth.

The rays given out did not penetrate paper or other obsta-
cles, hence they were similar to those given out by polonium.
They affected a photographic plate, and caused diamonds, zinc
oxide and other substances to fluoresce brightly. The body
differed from polonium in the fact that its activity did not decay.

This method of producing radio-acfive metallic coatings
has been patented by H. H. Lake, of the firm of Stahmer &
Co., Hamburg.2

1. Ber. Chem. Ges. 35, 2285 (1902), Chem. Zeit. 26, 895.

2. J. S. Chem. Ind. 22, 1136 (1903).

62 OTHER RADIO-ACTIVE BODIES AND

According to the periodic table of Mendelejeff, tellurium
should have an atomic weight less than iodine, whereas it has
actually been found to be greater. Pellini1 suggested that this
might be acounted for by the presence of a small quantity of
some element, which has a higher atomic weight (about 212),
similar to tellurium and analogous to the radio-active constitu-
ents of pitchblende.

Emanium.

Giesel2 has obtained from pitchblende a substance which
he has termed Emanium. It appears to be allied to lanthanum,
belonging to the cerium group of rare earths. The salts when
first prepared are not so active, but reach a maximum in about
a month, remaining so indefinitely; thus being similar to ra-
dium.3 The original /3-radiation becomes smaller trie longer
the substance is kept in solution. Runge and Precht obtained
a number of new lines in the spectrum, which gave essentially
the lines of lanthanum and a little cerium. The lines of thor-
ium, barium, and radium were not present. The anhydrous
chloride and bromide phosphoresce spontaneously. Glass ves-
sels in which the substance is kept for a month become violet
colored ; paper is turned brown and destroyed.

"If solutions of thorium, lanthanum, cerium, etc., to which
radium has been added, are precipitated with ammonia and
washed, the precipitates are adulterated with traces of radium
and show, besides (3- radiations, remarkably strong a- radiations,
but yet an emanation similar to the emanating substance."4

The discoverer attributes the induced radio-activity of
many substances rather to the emanating substance than to
the presence of minute traces of radium.

A splendid experiment, visible a great distance, may be
performed by blowing a current of air through tubes contain-
ing the material against a large screen of Sidots blende. The

1. Gazetta 33, 11, 55 (1903).

2. Berichte 35, 3608 (1902) ; 36, 342 (1903).

3- Ann. d. Phys. u. Chem. 69, 92 (1899).

4- Giesel, Berichte 36, 342 (1904).

THE SOURCES OF RADIO-ACTIVITY. 63

scintillations are most pronounced and are visible to the naked
eye, representing a large spinthariscope.

In studying the radio-activity of thorium, at the request
of the writer, Dr. H. S. Miner, of the Welsbach Light-
ing Company, saved certain ammoniacal washings obtained in
the process for the extraction and purification of thorium oxide
from monazite sand for the manufacture of gas mantles. The
ignited residue, obtained from evaporating over 100 liters of
this liquor, produced a marked effect upon the photographic
plate and showed nearly three times the radio-activity of thor-
ium by the electrical method, using the apparatus of Dolezalek.
The radio-activity remained constant through a number of
months. The body gave none of the chemical reactions and did
not show a single line of thorium in the arc spectrum.

The writer, working with Lichtenthaeler, has obtained
highly radio-active bodies, tested by the photographic method,
from thorium, cerium, didyium oxides, and the residual phos-
phates, extracted by ourselves from North Carolina monazite
sands. Further, we obtained an extremely active body by pre-
cipitating the sulphate solution with hydrogen sulphide, which
perhaps would, but not necessarily, indicate the presence of
polonium. Apparent verification is thus had of Giesel's work
on emanium.

E. Goldstein1 examined Giesel's emanium as obtained from
pitchblende and in its chemical behavior it seemed to be related
to cerium. On account of the small penetrative power of the
emanation, he assumed that the air exerted a strong absorption
of the latter so that its effects would be augmented in exhausted
tubes. This was verified by experiment. His experiments indi-
cated that the observed luminescence is due rather to a gas, than
a special form of energy issuing from the substance. When
cooling by means of liquid air exhausted tubes, where the active
matter had been introduced, Goldstein observed a very strong
luminescence on the wall, which, instead of rising in the closed

i. German Physical Society.

64 OTHER RADIO-ACTIVE: BODIES AND

portion of the tube, seemed to be confined to the zone imme-
diately above the level of the liquid air. That is, the phenom-
enon is characteristic of a definite temperature above the tem-
perature of liquid air. The emanation is given off at the tem-
perature of liquid air. He does not think that the emanation
energy in question is identical with that of radium, the distin-
guishing features being first, the absence of the coloration of
the tubes, and, second, the excessively low penetration.

Artificially Active Barium.

Debierne1 observed that when a highly radio-active salt
of actinium is added to a solution of barium chloride, the latter
becomes radio-active. If the barium be precipitated as sul-
phate and reconverted into the chloride, the actinium being
separated by means of ammonia, the barium retains some activ-
ity. This may be increased, depending upon the time of con-
tact, till it is several hundred times as active as uranium. It
is persistent throughout various chemical changes, it ionizes
gases, excites barium-platino-cyanide, and acts upon a photo-
graphic plate. Part of the radiation is deflected in a magnetic
field and the anhydrous chloride is also luminous. This barium
chloride, rendered radio-active, may be fractioned similarly to
the radium salts. The salts, however, do not give any of the
lines of the radium spectrum and their radio-activity gradually
diminishes in intensity.

THE NUMBER OF RADIO-ACTIVE ELEMENTS.

Soddy2 maintains that radio-tellurium is identical with
polonium and that there is no justification for the assumption
of a new element. Soddy acknowledges the existence of five
radio-active elements ; namely, uranium, thorium, polonium,
radium, and actinium. They may be distinguished in three
ways: They all give off a- rays ; all, with the exception of
polonium, give /3-rays ; uranium, thorium, and radium give

1. Compt. Rend. 131, 333 (1900).

2. Nature, March 17, 1904, pp. 461.

THE SOURCES OF RADIO-ACTIVITY. 65

y-rays. Polonium does not, and it is questionable about actin-
ium. Neither uranium nor polonium gives off a radio-active
emanation, while thorium, radium and actinium do. Those
radio-active substances which give off emanations impart activ-
ity to surrounding objects. That is, substances placed in the
neighborhood of thorium, radium and .actinium acquire an activ-
ity which is not permanent. The three substances which give
off emanations have their respective emanations distinguished
from one another by the time their activity lasts. The emana-
tions of radium continue through several weeks, those of thor-
ium only a few minutes, and actinium only a few seconds.

OTHER SOURCES OF RADIO-ACTIVITY.

C. T. R. Wilson1 reported the radio-activity of rain and
snow. Rutherford and Allan2 studied excited radio-activity
and its effect on the ionization of the atmosphere. The latter
regarded the radio-activity of rain and snow as derived from
the radio-activity of the atmosphere. J. J. Thomson3 reported
a radio-active gas in the Cambridge tap water, as did Bum-
stead and Wheeler4 for the surface water around New Haven,
Conn. Adams,5 considering the former, suggested the presence
of a small amount of radium in solution. Knetf observed that
the thermal springs of Karlsbad deposited small yellow tabular
crystals of barium suphate which were very radio-active.

McLennan and Burton7 reported the electric conductivity
of the atmosphere. The former" has observed the radio-activity

1. Proc. Camb. Phil. Soc. 12, 17 (1902); 13, 85 (1902).

2. Phil. Mag. 6, 704 (1902).

3. Proc. Camb. Phil. S. 123, 172 (1903)-

4. Am. J. Science (1904).

5. Phil. Mag. (6), 6, 563-

6. Sitz. Wien. No. n (1904). Nature 70, 160.

7. Phil. Mag. 6, 5, 699.

8. Nature 70, 151 '1904).

66 OTHER RADIO-ACTIVE BODIES AND

of natural gas, as well as experimented1 on the induced radio-
activity excited in the air at the foot of waterfalls. McLennan
and Burton2 also learned that metals generally possess more or
less radio-activity.

H. Lester Cook3 reported the penetrating radiation from
the earth's surface. Borgmann4 found the Russian muds radio-
active and that the air could be electrified by metals. Geitel
found a wire electrically charged and suspended in the air, as
well as the ends of pine needles, radio-active.

Elster and Geitel5 secured a radio-active emanation from
the air, from the soil, from cellars, mountain tops, mines, etc.
They6 also observed the radio-activity of sediments obtained
from evaporated spring water.

Miiller7 verified these observations and suggested the pres-
ence of another radio-active element accompanying radium.

Strutt8 studied the properties of a strong radio-active gas,
which he obtained from metallic mercury and learned 'that the
emanation behaved similar to that of radium, reaching one-half
value in a little over three days. Strutt9 also determined the
activity of a number of minerals, mineral waters, and ordinary
materials. Lester Cooke10 proved the universal occurrence of a
penetrating radiation similar to radium. It may have its origin
in the radio-active matter distributed throughout the earth and
atmosphere. Himstedt11 reported the radio-active emanation of

1. Phil. Mag. 6, 5, 419.

2. Phil. Mag. 6, 6, 343 (1903).

3. Phil. Mag. 6, 6, 403 (1903)-

4. Nature, 70, 80 (1904).

5. Chem. News 88, 29 (1903).

6. Phys. Zeit. 5, 321.
7 Phys. Zeit. 5, 367.
8. Phil. Mag. 6, 6, 113.

9- Proc. Roy. Soc. 73, 191 ; Phil. Mag. (6), 5, 680.
io- Phil. Mag. 6, 410 (1903); Proc. Roy. Soc. 68, 151; 69, 277;
Nature (1903), 3^9; 391, 4*4, 439-
ii. Ann. d. Phys. 13, 573.

THE SOURCES OF RADIO-ACTIVITY. 67

water and oil springs, and von Traubenberg1 considered the
absorption of the emanations of radium by the tap water of
Freiburg and other liquids.

Different meteorological conditions2 appear to determine
different degrees of radio-activity of the air. Much activity is
excited in fog. In cold, frosty weather the activity of the air is
very high. We have learned that tobacco smoke in the room
where one is making measurements by means of an electro-
scope increases the conductivity of the air. These things cause
variations in the leak of the instruments.

Concerning the general radio-activity of metals, Voller3
has called attention to a flaw in the experiments by McLennan
and Burton,* who claimed to be able to prove all metals radio-
active, as the potentials are very small and subject to many
errors. Hallwachs has pointed out the necessity of taking into
account all the E. M. F.'s of the electro-metric system. But
Voller, .on the other hand, says it cannot be denied that the
spontaneous projection of positive ions by all metals, if con-
clusively established,, would mean a very important advance in
our knowledge of the electrical phenomena.

Himstedt5 arrived at the conclusion that radio-active bodies
give off gaseous emanations and are widely diffused through-
out the earth. These emanations, being absorbed by water or
petroleum, are afterwards conveyed along by the latter to the
surface of the earth and are diffused into the air. On account
of the analogy between these emanations and those of radium,
he puts forward the belief that the^ are "identical. The ores
of uranium, from which the radium emanations are derived,
are therefore either widely diffused or there are other sub-
stances possessing, perhaps to a lower degree, the property of
giving off emanations. The absorption co-efficient of water

1. Phys. Zeit. 5, 130 (1904)-

2. London Lancet, Aug. 8th (1903).

3- Phys. Zeit. Oct. I (1903).

4- Electrician, Sept. n, 1903, p. 839.

5- Phys. Zeit. Apr. 15 (1904).

68 OTHER RADIO-ACTIVE BODIES

and petroleum, with respect to the emanations, is found to de-
crease with the increase of temperature.

Hot fountains have been found which show especially high
activity. The hypothesis is, therefore, put forward that the
amount of radio-active material increases for augmenting
depths. The radio-active components of the earth, conse-
quently, should have to be allowed for in accounting for the
temperature of the earth.

Schuster,1 referring to the matter of the cosmical radio-
activity, calls attention to the fact that any physical property
discovered in one element has always been found to be shared
by all. The possibility that radio-activity may be a common
property of all matter is immediately suggested. Radio-active
bodies, therefore, may be distinguished from other bodies by
the enormously exaggerated form in which they possess the
property.

We know that the earth must be charged with negative
electricity, which must be constantly renewed as there is con-
stant leakage. Elster and Geitel recently determined that a
body loses about 1-1/3% °f its charge per minute. If the air
near the ground has that conductivity, the earth should lose
about one-half of its charge in an hour. There can be little
doubt, therefore, but that we are living in an electric field
through which negatively charged particles are constantly
driven and which possesses an electric conductivity similar to
that found in the neighborhood of radio-active bodies. The
radio-activity of the ground air or water may thus be the con-
sequence of the emanations of a radio-active earth.

Schuster also pointed out the possibility of a correspond-
ing radio-activity of the matter in celestial bodies.

Rutherford, in a lecture before the Royal Institution in
London, stated that the amount of radium present and uni-
formly distributed throughout the earth would be sufficient to
account for all the heat lost from that body. On the assump-
tion that this is true» the period of time for the cooling of the
earth till it becomes uninhabitable, as calculated by Lord Kel-
vin, may be extended a few million years.

i. Chem. New? 88, 166 (1903).

CHAPTER IV.

RADIO-ACTIVE EMANATIONS AND SECONDARY
RADIO-ACTIVITY.

Variations in the radiations of thorium have been observed,
by the electrical method, when the substances were examined
in open vessels. Owens1 found that this was caused by the air
currents. When active matter was introduced into a closed
glass vessel the activity increased with time, finally reaching a
constant, which could be reduced by passing a stream of air
through the vessel. It was noted, also, that the radiations
passed through several thicknesses of paper, which absorbed
the a- rays. Rutherford2 discovered the emission of radio-
active particles from thorium compounds and named them
"emanations."

The ionizing substance acts upon a photographic plate and
diffuses through porous substances similar to a gas. (Fig. 36.)
It may be swept along by a current of air, passed through cot-
ton-wool, and bubbled through a solution of caustic potash
without any loss of activity. Thus it differs from the ions pro-
duced in gases by the action of radio-active substances. The
emanation cannot be dust of radio-active substances, which
would be screened out by the cotton-wool filters. Hydrogen
peroxide possesses the power of diffusing rapidly through por-
ous substances and acting upon a photographic plate, but it is
not radio-active. It is the radiation from the emanation, and
not the emanation itself, that produces the two characteristic
ionizing and photographic effects. (Fig. 37.)

i. Phil. Mag., Oct. (1899).
2.. Phil. Mag., Jan. (1900).

70 RADIO-ACTIVE EMANATIONS AND

To Rutherford and his co-workers are we indebted for
most of our knowledge of these and other emanations. Dorn1
made similar discoveries later with radium compounds. The
radium emanation loses its radio-activity at a different rate,
although it possesses many similar properties. Both behave
like a temporarily radio-active gas mixed in minute quantities
in the air in which they are conveyed.

Electromete*

Current

Fig. 36.

The apparatus may be used to demonstrate that the emanation of
radium is a gas and follows Gay-Lussac's law. The bulbs, A and B,
connected by a glass tube are evacuated, filled with the emanation and
placed as shown in the diagram. A rests within a cylindrical con-
denser, such as shown in Fig. 36, while reservoir B rests within a
constant temperature bath which may be heated by electricity. The
radiation of A possesses a definite value for one temperature, increasing
with the elevation of the temperature of B. The quantity of the
emanation which has been driven out corresponds to that which it
should be according to Gay-Lussac's law.

The emanations are given off more generously by the
radium compounds by heating, or on solution in water. Curie

i. Abh. d. Naturforsch. Ges. fur Halle (1900).

SECONDARY RADIO-ACTIVITY. 71

Fig- 37-

The figure shows apparatus, which may be used to illustrate the
diffusion and condensation of the emanation, in short demonstrate its
gaseous nature. Bulb A contains a radio-active solid or its solution.
B is coated on the inside with Sidot's blende, as is also the small bulb C.
Inserted in the connecting tubes, t and t' are the glass cocks R and
R'. R" serves to disconnect the apparatus from a vacuum pump. The
emanation collects in A, R being closed, if the radio-active solution be
allowed to stand ; if a solid be used, the experiment may be hastened by
gently heating the bulb. B and C are evacuated, R" closed. On opening
R, the emanation which has caused a slight glow in A, flows into B,
which becomes quite luminous. On closing R, placing C in a Dewar
bulb containing liquid air and opening R', the emanations are drawn
into C; after a time close R' and remove the apparatus. B will have
ceased glowing and C is exceedingly luminous in a dark room.

and Debierne1 found that if radium preparations were placed
in a vacuum tube, the vacuum was continually weakened.
Giesel2 observed that gases were evolved from solutions of
radium bromide, which Runge and Bodlander found, by spec-
trum examination, to be mainly hydrogen with about one-
tenth oxygen. m Ramsay and Soddy8 found that 50 m.g. of
radium bromide would evolve 0.5 c.c. of gas per day.

P. Curie4 and Rutherford and Soddy5 determined the rate
of decay of the activity of the emanation, which was found to

1. C. R. 132, 768 (1901).

2. Berichte d. Chem. Ges. 35, 3605 (1902).

3. Pro. R. Soc. 72, 204 (1903).

4. C. R. 135, 857 (1902).

5. Phil. Mag., April (1903)-

72 RADIO-ACTIVE EMANATIONS AND

be in accordance with an exponential law with the time, falling
to one-half value in about four days. Curie* further determined
that the rate of decay was not materially affected through such
a wide range of temperatures as +450° to — 180° C. Ruther-
ford and Soddy2 showed that the rate of decay for thorium
emanations was practically the same at ordinary temperature
a^1 at that of liquid air.

Debierne3 discovered the emanations of actinium: The loss
of activity is most rapid, falling to one-half value in a few
seconds. Giesel has obtained an intensely active emanation
from the ''emanating substance," which latter resembles lan-
thanum and cerium. By placing moist radium bromide on
the screen, Giesel4 noted the effect the radium emanation has
upon a screen of phosphorescent zinc blende. With the slight-
est motion of the air the luminosity of the screen is observed to
move in accordance with the air current. The same result
could be observed by placing a small bit of the bromide in a
tube and blowing air through the tube against different por-
tions of the screen. Screens of barium-platinum cyanide and
calcium sulphide did not become luminous under similar con-
ditions. When the screen was charged with negative electricity
the luminosity was most marked

The phenomenon upon which the spinthariscope of Sir
William Crookes5 depends is based upon the bombardment of
the zinc sulphide screen by the emanations. (Fig. 38.) Refer-
ring to this, Elster and Geitel6 noted their previous observation
of numbers of stars on an insulated zinc sulphide screen. A
calcium tungstate screen showed only general or ordinary phos-
phorescence and no scintillations. Geitel7 found the star-effect

•

1. C. R. 136, 223 (1903).

2. Phil. Mag., May (1903).

3. C. R. 136, 146 (1903).

4 Berichte Chem. Ges. 35, 3608 (1902).
5- Chem. News 87, 241 (1903).
6. Phys. Zeit. May (1903).

7 Aus der Denkschrift der Komission fiir luftelectrische'Forschun-
gen, Miinchen (1903), Chem. News 88, 29.

SECONDARY RADIO-ACTIVITY. 73

produced by soil emanations on a Sidot's screen charged nega-
tively to 2000-3000 volts.

Crookes and Dewar learned that the scintillations ceased
when the radium was cooled by liquid air, but the brilliancy
was quite as marked when the Sidot's screen was cooled and
the radium compounds were at normal temperatures. The high-
est vacuum attainable by cold does not affect the scintillations.

Fig. 38.

The Crookes Spinthariscope and the principle involved. On the
end of wire pointer, a, is placed a tiny speck of a strong radium com-
pound. This may be caused to move from place to place in front of a
zinc-blende screen, E, from which it is less than a millimeter distant.
Upon examining the screen in the dark, by means of the strong lens, L,
which may be focused, one sees numerous beautiful scintillations,
resembling the play of moonlight uporr a rippling lake. The impression
is given of the bombardment of the screen by many tiny particles, each
flashing as it strikes the restraining phosphorescent substance.

Curie and Debierne1 learned that in a vacuum a gas was
given off from radium which produced excited activity on the
glass walls of the vessel. The walls fluoresced, rapidly dark-
ened, and affected the photographic plate. This gas did not
show any lines in the spectrum, other than those of carbon
dioxide, hydrogen and mercury. They, also, learned2 that
many substances were phosphorescent under the action of the

1. C. R. 132, 548 (1901).

2. C. R. 133, 931 (1901).

74 RADIO-ACTIVE: EMANATIONS AND

emanation. They found in general that 'substances which are
phosphorescent in ordinary light become luminous, especially
zinc sulphide. They also observed that phosphorescence was
produced in Thuringian glass, showing most marked effects.
Kunz and the author1 noted that willemite is an even more
sensitive detector of the ft- and y-rays than barium-platinum
cyanide. Rutherford condensed the emanations of radium upon
a crystal of that mineral with most brilliant fluorescent effects.
The writer and Lockhart caused certain diamonds (tiffanyite)
and minerals, as greenockite and wollastonite, to glow bril-
liantly when the emanations were condensed upon them. Pecto-
lite and the spodumenes, especially the variety kunzite which
responds to the (3- and y-rays, did not phosphoresce2. Soddy
reports an observation contrary to this. The amount of excited
activity deposited is proportional to the amount of emanation
present, the distribution varying as the distance. Crookes3 has
caused white diamonds to assume the rare greenish color as a
result of the action of the emanations. The jewels were buried
for several weeks in radium bromide.

Rutherford and Soddy4 measured the emanating power of
different thorium compounds and learned that they varied very
much, although the percentage of the thorium present in the
compound was not very different. Rutherford5 learned that
the emanating power of ordinary thorium oxide is increased
several times by heating the substance to a dull-red, but when
heated to a white-heat the emanating power was greatly
reduced. When the heat is maintained red, the emanation
apparently continues to escape and the substance returns to its
original value on cooling ; whereas, after heating to a white-
heat, on cooling it has only about ten per cent, of the original

1. Science (N. S.), 18, 769 (1903).

2. Science (N. S.), 18, 303 (1903).

3. Chem. News 90, i (1904).

4- Trans. Chem. Soc. 321 (1902).

5- Phys. Zeit. 2, 429 (1901).

SECONDARY RADIO-ACTIVITY. 75

value. It has become "de-emanated." With lower tempera-
tures, the emanating power of thorium decreases quite rapidly1
being about ten per cent, of the original at the temperathre of
solid carbon dioxide. When the temperature is allowed to rise
back to the ordinary, the original value is recovered. Ruther-
ford and Soddy also verified the observations made by Dorn
that the emanating powers of thorium and radium compounds
are much affected by moisture, being greater in a moist than
in a dry gas.

Thorium and radium compounds which have been de-ema-
nated appear to recover the emanating property with time. It
is not known whether this is due to a renewal or alteration of
the substance which produced the emanation, or whether the
intense heating simply changed the rate of escape of the ema-
nation from the solid. The physical properties of thorium
oxide are altered by intense ignition. According to Rutherford
the color changes from white to pink and the oxide becomes
denser2 and is less soluble in acids. He dissolved a de-emanated
oxide, precipitate'd it as hydroxide, and again converted it into
the oxide. At the same time a sample of the ordinary thorium
oxide was subjected to similar treatment. "The emanating
power of both of these compounds was the same and was from
two to three times greater than that of ordinary thorium." It
should be noted that Rassignal and Gimingham3 have deter-
mined the rate of decay of the emanations as 51 and not 60
seconds, as given by Rutherford.

As a general rule, an increase of temperature in a solution
of a salt of thorium or radium greatly increases the emanating
power. From this it would seem that the original power of
producing emanation persists in the atom. (See Chapter V.)

1. Rutherford and Soddy, Phil. Mag., Nov. (1902).

2. See the author's paper, "Thorium; Carolinium, Berzelium;"
Journ. Am. Chem. Soc. 26, 922 (1904).

3. Phil. Mag. (6), 8, 107.

76 RADIO-ACTIVE EMANATIONS AND

Henning1 found that the radio-activity induced in metallic
wires by thorium oxide depended upon the surface area of the
wire, the volume of the containing tube, the fall of potential,
and the thickness of the layer of the thorium oxide.

Rutherford and Soddy,2 in a comparative study of the
emanations of radium and thorium, found that as far as that
property is concerned, they are closely allied, both producing
radio-active emanations, and they in turn excite radio-activity
in surrounding objects. The difference is very marked, how-
ever, in the rate at which the activity of the emanation decays.
The intensity of the thorium emanation falls to one-half value
in one minute, and that of the radium in about four days ; while
the excited radio-activity due to radium decays much more
rapidly than that produced by thorium.

Curie and Danne* have shown that the radium emanation
is absorbed by lead, paraffin and caoutchouc.

Touching the rate at which emanations are given off by
solid radium compounds or when they are in solution, Ruther-
ford and Soddy4 have called attention to the following interest-
ing point:

By theory, the amount of emanation stored up in a non-
emanating radium compound is likely to be nearly 500,000
times the amount produced per second by the compound. -"By
experiment the figure obtained was 463,000. Taking other
things into consideration, this would indicate that the produc-
tion of, or ability to produce, the emanation is the same with
the solid compound as when in solution. It is occluded in the
solid, and therefore given off slowly, while in a solution it is
given off as fast as produced. Rutherford is of the opinion
that the occlusion is not connected with the radio-activity of
radium. The apparent" occlusion of helium by minerals is
analogous. The gas is driven out only in part by heat, com-

1. Ann. Phys. (IV), 7, 562 (1902).

2. Phil. Mag. (IV), 5, 445 (1903).

3. Compt. Rend. 136, 364 (1903).

4. Phil. Mag., April (1903).

SECONDARY RADIO-ACTIVITY. 77

pletely by solution. The writer and Lockart heated nearly all
the rare-earth minerals and condensed the gases evolved by
liquid air. All the helium bearing minerals gave off an emana-
tion or something of a similar nature, which on refrigeration
caused diamonds and a Sidot's blende screen to fluoresce. Other
radio-active minerals, not containing helium, failed to respond
in a like manner. Strutt1 heated several minerals, samarskite,
pitchblende, fergusonite, malacone, zircon, and monazite, col-
lected the emanation evolved and measured the rate of decay.
No new emanation was recognized. By drawing air over the
cold minerals he learne.d that only a very small portion of the
emanation is given out unless they be heated. All the minerals
used contained helium and one, malacone, has been shown by
Ramsay and Travers2 to contain argon as well.

The question of the origin ^f the emanations of thorium,
which according to Rutherford and Soddy8 are produced by
thorium-X and not thorium itself, present much that is of inter-
est. Thorium oxide, freshly prepared by heating the hydroxide
produced by precipitation with ammonia, shows no emanating
power. In a month it has nearly reached a maximum in its
recovery. The thorium-X, obtained by evaporating the filtrate
from the ammonium hydroxide precipitation, gives out profuse
emanations. The emanating power decreases rapidly and by
the time the thorium has recovered its normal activity, the
emanating power of the thorium-X has nearly disappeared.
Considering the rates of decay and recovery, apparently the
radiations are produced as thorium-X is changed into the
emanation. With radium, however, no intermediate stage —
radium-X — has "been observed. Rutherford regarded the
emanation as being produced directly from the element.

The emanations of radium and thorium were thought at
one time to give rise only to a-rays. Curie and Debierne4 found

1. Proc. Roy. Soc. 73, 191.

2. Proc. Roy. Soc. 64, 131.

3. Phil. Mag., Nov. (1902).
4- C. R. 133, 931 (1901).

78 RADIO-ACTIVE EMANATIONS AND

the amount of excited activity in a closed vessel containing a
radium compound unaffected by the pressure and nature of the
gas. The rate of decay of the emanation has been shown to be
the same under all conditions of concentration, pressure and
temperature, provided the rate of supply of the emanation be
constant. (Fig. 39.)

Fig. 39-

Rendering bodies active in a closed receptacle through the influence
of the emanations. The radium salt is placed in a small dish, a, near
various substances, A, B, C, D and E, it matters not what be their com-
position (lead, copper, glass, cardboard, ebonite, etc.)- These sub-
stances acquire activity, may be removed, and their activity measwred.
The activity increases from the beginning according to the time which
the substance remains in the receptacle. A limit-value is reached after
a certain length of exposure.

Chemical Nature of the Emanations.

In their earliest experiments Rutherford and Soddy1 sub-
mitted thorium emanations, obtained by passing air over thor-
ium oxide, to a most stringent treatment. They found it unal-
tered after being heated by electricity to the highest tempera-
ture attainable, when passed over platinum black, cold and hot,
red hot lead chromate, magnesium powder, and zinc dust. The

i. Phil. Mag., Nov. (1902).

SECONDARY RADIO-ACTIVITY. 79

only gases known to withstand such drastic treatment are those
of the argon family.

Later Rutherford and Soddy1 sparked the emanation from
radium in a glass tube, containing oxygen and an alkali, heated
it red hot in a magnesia lime tube for several hours, and ob-
served no diminution in its rate of discharge. They learned
that a tube containing a large amount of radium emanations
phosphoresced brightly under the influence of the rays given
out. The removal of the emanations from one point to another
in the tube was easily observed in a darkened room by the
luminosity of the glass. The luminosity of the emanation in-
creased when the gas was compressed.

Rutherford and Brooks2 and Curie and Danne,3 as reverted
to, learned that the emanation of radium, like a gas, always
divided itself between two connected reservoirs in proportion
to their volumes. By determining the co-efficient of the diffu-
sion of the emanation in the air, they learned that the molecular
weight of the gas must be large. The same was demonstrated
for thorium. Crookes4 directed attention to the difference in
the rate of diffusion of the "radiant matter" of radium, actin-
ium, and polonium through air. The last is the slowest. The
"emanations" from hydrogen peroxide are not carried through a
tube by air.

«Wallstade,5 by determining the co-efficient of the diffusion
of radium emanations into various liquids, arrived at the same
conclusion as to the gaseous nature of the emanations.

Rutherford and Soddy6 learned that the emanations from
thorium and radium were condensed at a temperature of liquid
air. By placing a phosphorescent zinc sulphide screen, or a
small piece of willemite in a tube, the presence of the emana-
tions is readily observed through the glowing of either of these

1. Proc. Roy. Soc. 72, 204 (1903).

2. Chem. News (1902).

3- C. R. 136, 1314 (1903)-

4 Proc. Roy. Soc. 69, 413 (1902).

5- Phys. Zeit. 4, 721 (1903).

6. Phil. Mag., Nov. (1002), and (6), 561.

RADIO-ACTIVE EMANATIONS AND

substances. The luminosity of the screen is due in part to the
radiation from the emanation and in part to the excited radia-
tion caused by it. The accompanying figure (Fig. 40) illus-
trates the very simple methods for the condensation of the
emanations. The temperature of the condensation of the thor-
ium emanation is not sharply defined, but is probably — 120°
C, while the temperature for the radium emanation is about
— 150° C. Their actual quantity is almost infinitesimally small.
They are invisible and unrecognizable, but their presence is
readily detected by their property of radio-activity.

Fig. 40.

Simple apparatus for condensing the emanations. A radium compound
or other radio-active substance giving emanations is placed in small tube,
A, connected by heavy rubber tubing to another tube, which projects
through a two-hole rubber stopper nearly to the bottom of the thick-
walled test-tube (C). The exit tube, also provided with a cock, passes
from just within the test-tube through the stopper to the vacuum pump.
Within the test-tube may be placed a small piece of Willemite (Kunr
and Baskerville), a diamond, or zinc sulphide screen. The tube is
exhausted by opening cock E, B remaining closed. After exhaustion E
is closed, C placed in liquid air in the Dewar bulb (D). A is gently
heated, B opened and at once the emanation rushes over and is con-
densed on the materials mentioned. The glow is very beautiful. By
closing B the imprisoned emanation may be held for hours or days.

SECONDARY RADIO-ACTIVITY.

CONDENSATION
RADIUM EMANATION

urn
ation

WillBinitc--^

Liquid Air.

\ '

Fig. 40 A

The emanations from thorium and from radium are quite
distinct from each other in two particulars : first, the differ-
ence in condensation, as just noted ; and second, their difference
in radio-activity. The rate of decay of the radium emanation
is about 5000 times slower than that of the thorium emanation.

As a result of the investigation of the heat emission of the
radium emanation, it has been learned by Rutherford and
Barnes1 that the emission corresponds, approximately, to the
activity as measured by the a-ra)^s. That is, it accompanies the
expulsion of the a- particles and is proportional to the number
expelled. The emanation is responsible for about seventy per
cent, of the heat effect of radium. The amount of the emana-
tion is extremely small, but it has been calculated by Rutherford
that one c.c. of the emanation at standard pressure and tem-
perature would emit about 3x1 o7 gram calories of heat. This
would indicate that heat would be produced at such a rate as
to melt an ordinary glass tube which might be used to contain
the emanation in quantity.

"If the atomic weight of the emanation is taken to be about
200, it can be calculated that one pound weight of the emanation
would initially radiate heat at the rate of about 8000 horse-
power, and in the whole course of its heat emission would radi-
ate an amount of energy corresponding to 40,000 horse-power

i. Phil. Mag. (6), 207 (1904).

RADIO-ACTIVE EMANATIONS AND

Fig.4i.— PHOSPHORESCENCE CAUSED BY THE EMANATION

OF RADIUM.

A vacuum is formed in this reservoir through the tube, T, and air
charged with emanation is afterward let in from a reservoir, A. The
tube, A, contains a solution of a radium salt, and the emanation dis-
engaged has accumulated in the gaseous part. As soon as the cock, R,
is opened, the reservoir, B, becomes very luminous, and the light
emitted by the sulphide of zinc is sufficiently bright to permit of reading
being done at a distance of 4 or 8 inches from the tube.

days. In order to obtain such an amount of emanation about
seventy tons of radium would be required."1

i. "Radio-activity," Rutherford, p. 247, MacM. Co.

SECONDARY RADIO-ACTIVITY. 83

Beilby1 found that glass was decomposed in the neighbor-
hood of certain hot metals, as gold and platinum. This inten-
sification of chemical action he attributed to the emanations
from the metals, although they are not radio-active, as the term
is used.

Sir William and Lady Huggins2 photographed the phos-
phorescent spectrum of a radium compound by a 72-hour ex-
posure. They are reported3 as having found five of the eight
lines observed as coincident with helium. This appears to have
been erroneous, as the lines were really found to have agreed
in position and intensity with the band spectrum of nitrogen.
Later Crookes and Dewar4 learned that the nitrogen spectrum
did not appear when the radium bromide was placed in a highly
exhausted quartz tube. Yet Curie and Dewar5 secured notable
amounts of nitrogen which was occluded by the purest radium
bromide. .4 of a gram of pure dry radium bromide were left
three months in a glass bulb connected with a small Geissler
tube in a mercury manometer, a high vacuum being made in
the whole apparatus at the beginning. During the entire three
months one cubic centimeter of gas per month at atmospheric
pressure was given off continuously from the radium salt.
Spectroscopic examination showed only the presence of hydro-
gen and mercury vapor, the former doubtless due to a small
amount of water, native with the radium salt and decomposed
by the radium. The same sample was taken to England and
used by Dewar at the Royal Institution for measuring the heat
given off at low temperatures. It was in a quartz bulb provided
with a tube of the same substance. The bulb was evacuated
and the tube heated to the fusion point of salt. The gas given
off by the bromide was collected by a mercury pump. After
passing through a set of new tubes, cooled by liquid air, which

1. British Association, Southport Meet. (1903), Chem. News 88, 178.

2. Proc. Roy. Soc. 72, 196 and 409 (1903).
3- Science (N. S.), 18, 186 (1903).

4- Brit. Assoc. (1903).

5- Compt. Rend. 138, 190.

84 RADIO-ACTIVE EMANATIONS AND

condensed the greater part, the remainder of the gas was col-
lected in a test tube over mercury. This amounted to 2.6 c.c.
at atmospheric pressure. Part of the radium emanations was
brought over and was radio-active and luminous. The light
given off by the gases in the test tube, after three days' expos-
ure with a photographic quartz spectroscope, gave a discon-
tinuous spectrum with three lines coinciding with the three
principal bands of nitrogen, namely, 3,800, 3,580, and 3,370.
The glass tube took on a deep violet hue and half the volume
of gas was absorbed during the three days. On passing a
spark through the gas in a Geissler tube, the nitrogen bands
also appeared. On condensing nitrogen with liquid hydrogen,
a high vacuum was produced in the Geissler tube and the spark
showed only the nitrogen present. The quartz tube was heated
until the bromide of radium melted and deprived of all the
occluded gases, sealed by an oxy-hydrogen blow-pipe, when
the vacuum was made, and carried to Paris. Twenty days
after the sealing Deslandres examined it spectroscopically by
illuminating the tube with an induction coil, using two rings
of tin foil around the tube as the poles and secured the entire
spectrum of helium. This was noted even after an exposure
of three hours with the quartz spectroscope.

These observations were in accord with the analogous
investigations of Ramsay and Soddy1.

Rutherford and Soddy2 first suggested that the emanation
might consist of helium. The latter carried the problem to the
master Ramsay, whose laboratory possessed superb facilities
for handling and investigating small amounts of gases. They
removed the hydrogen and oxygen, liberated in large quantities
from a water solution of the bromide, condensed the emanation
and carbon dioxide by liquid air and found the characteristic
D3 line of helium. Later they found not only the complete
spectrum of helium XX- 6677, 5876, 5016, 4972, 4713 and
4472, but three other lines which were not identified, namely,
XX- 6180, 5695, and 5455.

1. Compt. Rend. 138, 190.

2. Nature 246 (1903), and Proc. Roy. Soc. 72, 204.

SECONDARY RADIO-ACTIVITY. 85

For a fuller discussion of the emanations see Chapter V.

Excited Radio- Activity.

Substances in contact with radio-active bodies acquire the
power of affecting a photographic plate, and ionizing gases. In
making certain radio-active experiments, therefore, it is of the
utmost importance that precautions be taken to avoid the pres-
ence of other radio-active substances in the room.

The Curies1 first observed this property of inducing activity
by radium and Rutherford2 noted it for thorium. Solid sub-
stances placed within a closed vessel, which contains an ema-
nating compound, become radio-active. The intensity of the
radio-activity varies directly with the proximity. With radium
preparations it is different. After an exposure of several hours
the excited activity is independent of the position or composition
of the plates. Mica, ebonite, cardboard, and copper exhibit
equal amounts of activity. It is dependent upon the extent of
surface exposed. (See Fig. 39.)

Becquerel3 examined the secondary radio-activity of metals,
which was attributed to the absorption of the incident radia-
tion. The phenomenon appeared to correspond to that of fluor-
escence or phosphorescence with regard to light and analogous
to the secondary rays derived from Rontgen rays discovered
by Saginac. They are less penetrating than the original, but
consist of portions, (a) not deviable by a magnetic field, but
easily absorbed, (b) deviable and apparently identical with
cathode rays, and (c) not deviable, but very penetrating.4

This property of exciting radio-activity appears to be due
to the emanatio'ns and proportional solely to the amount pres-
ent. It may be concentrated upon the negative electrode in a
powerful electric field.

1. C. R. 129, 714 (1899).

2. Phil. Mag., Jan. and Feb. (1900).

3- Compt. Rend. 132, 7.

4- Compt. Rend. 132, 7, 12, 371 (1901).

86 RADIO-ACTIVE EMANATIONS AND

Fig. 42.

Residual activity. The pen was radiographed by a glass tube, which
contained 5 mgms. of radium bromide, but which had been empty a
month.

The activity which platinum wire acquires by being placed
in thorium solutions may be removed by acids like nitric, hydro-
chloric and sulphuric.1 The deposited radio-active matter
may be largely removed by scrubbing the wire with emery
paper. No increase in the weight of the wire has been observed
before or after it becomes active. No difference is noted under
the microscope. Whatever it is, therefore, it must be vastly
more active than radium itself. Rutherford has termed this
"radio-active matter" Emanation-X, as it is quite distinct
chemically and physically from the emanation which produces
it. This we appreciate at once when we recall that the emana-
tion is a gas, unaffected by chemicals, while the emanation-X
is a solid and readily soluble in acids. Platinum wire becomes
active by exposure to the emanations of thorium, but loses its
activity when raised to a white-heat. Gates2 learned that the
activity was not destroyed, however, but transferred to the walls

1. Rutherford, Phil. Mag., Feb. (1900).

2. Phys. Review, p. 300 (1903).

SECONDARY RADIO-ACTIVITY. 87

of the vessel in which the heating had taken place. The same
was learned of activity induced by radium.

Miss Brooks has shown that dust particles, as other solids,
acquire radio-activity when enclosed in the presence of emana-
tions. M. and Mme. Curie1 found that substances after a long
exposure to radium did not lose all of their acquired activity.
Giesel2 has found that the radiations from an excited platinum
wire consist entirely of a-rays. Rutherford3 found the residue
from a solution of the deposited matter after evaporation re-
tained its activity. It was retained when it was enveloped in a
copper coating electrolytically deposited. Von Lerch4 studied the
emanation-X of thorium and learned that copper or magnesium
wires served to take up most of the active matter. When these
metals were dissolved and precipitated as different compounds
the activity remained and decayed at the normal rate ; namely,
one-half within 1 1 hours.

Fig. 43-

Induced radio-activity. The key was radiographed with water
rendered active by allowing a tube of radium salt to remain in it some
time and then removing it.

Barium sulphate also carried down the emanation-X by
precipitation. Different metals dipped into active solutions
varied in their conduct. Zinc removed almost all of the activity.
Iron, nickel, aluminum, copper, lead and cadmium, also, became
active, while platinum, palladium and silver did not. Pegram*

1. Thesis, 1903, 116.

2. Ber. d. deutsch. Chem. Ges. 36, 2368 (1903)

3. Rutherford, Phys. Zeit. 3, 254 (1902).

4. Annal. (4), 745 (1903)-

5. Phys. Review, Dec. (1903)-

88 RADIO-ACTIVE EMANATIONS AND

electrolyzed thorium solutions obtaining a radio-active deposit
of lead peroxide on the anode from the commercial and the

Fig. 43-

This is a radiograph of a gold fish which had been placed in water
rendered radio-active by having suspended in it for twenty-four hours
a closed tube containing ten milligrams of radium of high activity. By
this process the water was rendered radio-active and the fish was then
placed in the water, and although the radium had been entirely removed,
the fish itself was rendered radio-active, and when placed on a photo-
graphic plate, photographed itself by its own radio-activity.

Fig. 44.

Induced radio-activity. The fish made the auto-photograph after
being subjected to the action of radium bromide, 300,000 activity.

SECONDARY RADIO-ACTIVITY.

so-called chemically pure salts. With pure preparations fur-
nished by the author no visible deposit was found, but the
anode was active. Its activity decayed to half value in an hour,
whereas the rate was 1 1 hours for the commercial preparation,
the normal rate determined for all the thorium preparations
hitherto used. This emphasizes a point to which the author
has frequently directed attention ; namely, that most investiga-
tions on the activity of thorium have not been made with
preparations of sufficient purity. Nor have preparations been
used whose life-history has been known.

Rutherford and Barnes1 determined the heating effect of
radium emanations. This can best be illustrated, as shown by
Rutherford :

Active products

Nature
of
rays

Percentage pro-
portion of total
activity meas-
ured by rays

Percentage
proportion of
total heating
effect

Radium freed from
active products

a rays

Emanation
Emanation X(ist change)

a rays
a rays

18 1
[33

15)

(2d change)
(3d change)

No o- rays
a, (3 & y rays

°1

42 J

The heating effect which accompanies the expulsion of the
a- particles appears to be approximately proportional to the
number expelled.

Rutherford2 learned that under low pressures the excited
activity produced by thorium is found on both anode and
cathode, it matters not what the strength of the electric field
may be.

1. Phil. Mag. (VI), 7, 202 (1904).

2. Phil. Mag., Feb. (1900).

90 RADIO-ACTIVE EMANATIONS AND

Curie and Debierne1 learned that the amount of excited
radio-activity produced by a radium compound was much re-
duced when the gas within the vessel was kept at a low pres-
sure. They2 also learned that induced activity would result
from the presence of a solution of a radium salt. The action
is more regular and intense when a solution is used. It pro-
duces phosphorescence of glass. This is independent of the
position of the radium solution provided sufficient time be
allowed.

The excited radio-activity is attracted to the cathode in a
strong electric field. Fehrle3 learned that excited activity fol-
lowed the lines of force in an electric field. It appears that the
radio-active matter, therefore, is transported by positively
charged carriers.

Giesel4 reports that his "emanating substance" gives rise
to a type of radiations which he termed E-rays. By electrifying
a zinc sulphide screen negatively, more brilliant luminous effects
were produced, which would indicate that the carriers of the
excited activity of his emanation substance have a positive
charge. Batelli and Maccarone,5 by using an especially sensi-
tive electrometer of small capacity, suitable for working at
ordinary or liquid air temperatures, found that the emanation
carries no charge. They are not atomic residues which the
positive ions have lost, but the positive ions themselves. McClel-
land,6 also, arrived at the same conclusion.

Debierne7 showed that barium could be rendered artificially
active by precipitation from a solution of actinium. A very
active barium chloride was made in this way, concentrated like
radiferous chloride, but no spectroscopic lines of radium were

1. C. R. 132, 768 (1901).

2. C. R. 133, 23, 931.

3. Phys. Zeit. 3, 130 (1903).

4. Berichte 36, 342 (1903).

5. Atti. R. Acad. d. Lincei Roma (5), 13, 539 (1904).

6. Phil. Mag. 6, 355 (1904)-
7- C. R. 131, 137

SECONDARY RADIO-ACTIVITY. 91

obtained. The activity of the barium decayed to about one-
third its value within three months.

Debierne,1 also, obtained a large amount of emanation
from actinium. Its activity decays very rapidly. The emana-
tion produced excited activity on adjacent bodies. He attrib-
uted the excited activity of actinium to "ions activants."

The induction of radio-activity and ionization of gas are
quite distinct from one another. Therefore, the actinium
emanation must be regarded as containing two sorts of energy.2
That is, the substance containing actinium seems to emit a sec-
ond emanation which decays much more slowly than the first
one described.

Giesel, four years ago, found that a stick of bismuth would
become active when placed in a radium solution. He intimated
that polonium was practically radiferous bismuth. Madame
Curie repeated the work by fractionation and obtained a bis-
muth two thousand times as active as uranium.

Again, Giesel3 found that his bismuth plate remained active
after every effort had been made to remove all traces of radium.
It gave out only a-rays and therein resembled polonium and
radio-tellurium.

Mme. Curie4 developed a law for the dissipation of excited
radio-activity in an unconfined air space. The intensity for
radium is reduced to one-half value in twenty-eight minutes.
For actinium and thorium the loss requires greater time. Within
a closed space, the emanation from radium may be said to dis-
appear spontaneously as a function of the time, going to one-
half in four days, according to Rutherford.

According to 'the law for unconfined spaces, the activity
induced should be almost imperceptible. Certain substances, as
celluloid, paraffine, and caoutchouc, however, lose their acquired
activity with great slowness, sometimes requiring fifteen or

1. C. R. 136, 446, 671 (1903).

2. C. R. 138, 411 (1904).

3. Berichte 36, 2368 (1903).
4- Thesis (1903).

92 RADIO-ACTIVE EMANATIONS AND

more days. In losing it, they also induce radio-activity. Doubt-
less, this lag, or special induced activity, has much to do with
the unique observations of Metzenbaum,1 who caused zirconium
and yttrium compounds to affect a sensitive photographic plate
similarly to thorium compounds. His experience is unique and
contrary to that reported by others. Perhaps it may be due to
the admixture of small amounts of radium. This is the expla-
nation he offers for the activity of thorium. Haitinger has
extracted radium from commercial thorium oxide.

Metzenbaum2 produced skiagraphs with metallic aluminum
by placing it directly on the sensitive gelatine. A shield of
black paper or glass prevented the darkening of the plate. This
can be readily attributed to chemical or electro-chemical action.
He placed closed tubes of radium preparations in various pow-
ders for several days. After removal, he obtained negative
results as to induced activity, tested photographically and with
the electroscope.

Previously, much prominence was given by the secular
press to the reports of exciting activity in salt and other solu-
tions, which might be used internally for specific therapeutic
effects. (See Chapter VI.)

Heydweiller3 reported no loss of weight from a closed
radium tube. Dorn/ however, reported diminution, while
Forch observed "no change. Davis, in our laboratory, was un-
able to detect any loss in weight of a closed tube containing a
gram of chloride, 7000 activity. So far no satisfactory experi-
mental evidence, as to the loss of weight by radium compounds,
has been offered. Piffard5 calls attention to the fact that no
authoritative statement has been given as to the rendering of

1. "Radium, Radio-active Substances and Aluminum," Cleveland,
O., '04. Scientific American, May 14,' 1904, and Cleveland Med. J.,
May, '04.

2. Loc. cit.

3- Phys. Zeit. 4, 81 (1902).

4- Phys. Zeit. 4, 530 (1903).

5- "A Few Words Concerning Radium," Medical Record.

SECONDARY RADfo-AcTiviTY. 93

water or other substances radio-active by the presence of a
closed tube of radium. He further detected defects in tubes,
air bubbles, etc., and regards the statements concerning induced
activity by means of closed tubes as based upon the use of
defective tubes. As Curie and Rutherford have shown, induced
activity requires a naked exposure of radio-active bodies. It is
superficial, the real extent depending entirely upon the depth to
which the emanations or their products have penetrated. It
has bleen definitely proved that the emanations consist of mater-
ial particles. Their expulsion and consequent transference,
when radio-active substances are exposed, must, therefore,
mean a corresponding loss in weight of the original substance.

To explain the phenomenon of induced radio-activity, two
hypotheses have been put forward. The first states that the
inactive molecules of almost any substance after being mixed
with an active substance like radium temporarily acquire the
property of radio-activity. The second hypothesis states that
inactive bodies become active by association with active sub-
stances by removing a small portion of the latter, or by remov-
ing a radio-active product of the element. Thus the excited
activity may be permanent or temporary, decaying according
to the law governing the radio-active product removed. From
the work of von Lerch, already mentioned, the latter appears
to be the most acceptable explanation.

94 THEORIES OF RADIO-ACTIVE PHENOMENA.

CHAPTER V.
THEORIES OF RADIO-ACTIVE PHENOMENA.

Naturally the ideas of Madame Curie, which led to the
brilliant discovery, deserve first mention. Her experimental
data warranted the assumption that racfio-activity is an atomic
and not a molecular phenomenon, although she does not com-
mit herself unreservedly to that explanation.

Becquerel1 used the following hypothesis for his investi-
gations : radio-active matter, according to J. J. Thomson, con-
sists of negatively and positively charged particles. As shown
by Thomson's work, the negative particles have a mass of about
i/iooo that of hydrogen, and the positive particles have a mass
about equal to hydrogen. The former (or ^8- rays) are pro-
jected at a very high velocity, while the latter are compara-
tively sluggish, constituting the emanation which may be de-
posited upon the surface of bodies and which give rise to
exicted activity.

Becquerel,2 further, having noted that the activity of uran-
ium was not constant, as previously noted by Giesel and
Crookes, suggested that the emission of the deviable rays be
identical with the cathode rays and the cause of the non-
deviable radiation so much like the X-rays. It was thus com-
parable to the evaporation of an odorous body. The dissipated
energy would be given out from the active body itself, but the
corresponding loss of weight would be too small to be observed.

Rutherford and McClung3 previously learned that the
energy given out in the form of ionizing rays was 3000 gram-
calories per year in radium, 100,000 activity, or with the pure

1. C. R. 133, 979 (1901).

2. C. R. 133, Dec. 9 (1901).

3. Phil. Trans. 25 (1901).

THEORIES OF RADIO-ACTIVE PHENOMENA. 95

radium preparation, 1,500,000 activity, an emission of energy
in the gas, as a-rays, of about 45,000 gram- calories per year.
It was suggested that this energy might be derived from a
re-grouping of the atomic constituents of radio-active elements.
Even before that, Rutherford1 believed that thorium emanations
and excited activity were due to radio-active matters. With
Brookes, and later Soddy, he learned that the emanations of
thorium and radium behaved like gases, that they produced
excited radio-activity, that they diffused through air like gases
of heavy molecular weight, and that they behaved very much
like the chemical inert gases, with the exception that they were
dissolved in some acids and not in others.

Curie2 differed from Rutherford, calling attention to the
fact that no spectroscopic evidence of the gas had been obtained
and, that, also, the emanation disappeared when in a sealed
vessel. He regarded the emanation as consisting of centres
of condensed energy, attached to gas molecules, and moving
with them. Rutherford3 claimed that the failure to detect the
gas spectroscopically could be accounted for through the mi-
nute quantity of the emanation present (one gram of radium
produces 3.3xio"4 c. c. at atmosphere pressure and tempera-
ture4) although the electrical and phosphorescent actions were
very marked with the amounts to be had: Rutherford and
Soddy0 studied uranium, thorium and radium, condensed the
radio-active emanations at the temperature of liquid air, demon-
strated that the a-rays consisted of positively charged bodies,
atomic in size, and projected with a great velocity. This proof
of the materiality of the emanations forced upon them the
necessity for assuming the continuous production, by thorium
and radium, of new kinds of active matter which possess tem-
porary activity and differ chemically from either of those two

1. Phil. Mag., Jan. and Feb. (1900).

2. C. R. 136, 223 (1903).

3. Phil. Mag., April (1893).

4. Phil. Mag., May (1903).

5. Trans. Chem. Soc. 81, 321, 837 (1902), and Phil. Mag., Sept. and
Nov. (1902), Feb., Apr. and May (1903).

96 THEORIES OF RADIO-ACTIVE PHENOMENA.

elements. Further, it was learned that the radio-activity as-
sumes a constant, being a resultant equilibrium between the
processes of production of active matter and the alteration of
those already produced.

Curie and Laborde1 suggested that the heat may as well be
supposed to come from the breaking up of the radium atom as
from energy absorbed by it from some outside source. J. J.
Thomson2 postulated the emission of energy as being due to
some internal changes in the atom, and that a large store of
energy would be released by a contraction of the atom.

Fillipo Re3 put forward his belief that particles have pre-
viously been free and that they constitute nebulous formations
of extreme tenuity. In time they became reunited around
centres of condensation, giving rise to small suns, as it were,
which by ulterior contraction, take stable and definite form.
These make up the atoms of ordinary chemical elements. As
we know them, they may be compared to small extinct suns.
The larger suns, not yet extinct or cold, constitute the atoms
of radio-active bodies, hence the heat absorbed with these sub-
stances. Latterly this idea has come forward with greater
prominence.

Hudson Maxim* accounted for its luminous, heat-giving
effect by asserting that radium has a property opposite to ultra-
violet rays, that the high electric waves impinging upon radio-
active substances slow down to waves of lower pitch, some cor-
responding with visible light, others with heat. In the same
manner an opaque body like a piece of smoky glass, will get
hot in the direct sunlight by a slowing down of the higher
light rays to the lower pitch, which are sensed as heat. Two
years later Lord Kelvin, in a paper before the British Associa-
tion, presented the same theory, using nearly identical illustra-
tions.

1. C. R. 136, 673 (1903).

2. Nature (1903), 601.

3. C. R. 136, 1393 (June 8, 1903).

4. Electrical Are (1901).

THEORIES OF RADIO-ACTIVE PHENOMENA. 97

DuPont1 suggests that radio-active substances are catalytic
agents, radium being very powerful; that radio-activity is a
form of catalysis, and that the action which radium has upon
surrounding bodies is due to this cause.

A catalytic agent is a body which by its mere presence
accelerates chemical reaction or causes chemical reactions to
take place within other bodies which would not react upon
each other or would react very slowly, except for its presence.
As an illustration, we may cite the action of platinum in the
formation of sulphur trioxide from sulphur dioxide and
oxygen.

The converse order was suggested, namely, that radio-
activity might be used as a key to the solution of the problem
of catalytic action. Radium has the effect of discharging elec-
trically charged bodies. Riecke regards atoms as electrically
charged. Perhaps the effects of radium upon animal tissue
may be due to the discharging of negative electricity, which
holds certain molecules from uniting with other molecules,
thereby bringing about chemical reactions which under normal
conditions are impossible of being effected.

Attention is called to the phenomena observed within a
spinthariscope. The emanations do not resemble light rays
thrown off from luminescent bodies, but are more like a
meteoric shower, or a lot of miniature bomb shells exploding.
Maxim likens the action of radium to the familiar theory of
the thunder storm. That is, small aqueous vesicles forming
the clouds, each vesicle charged with a small amount of elec-
tricity, unite with one another forming larger vesicles. As
they are spherical* the larger vesicles show a smaller surface
in proportion to the mass ; consequently the electrical tension
upon the surfaces becomes greater as the vesicles grow into
drops of water and it is the uniting into one great electrical
spark of an infinite number of small electrical sparks passing
from drop to drop that produces trie lightning flash and clap

i. Scientific American Supplement, Apr. 9 (1904), P- 23631.

98 THEORIES OF RADIO-ACTIVE PHENOMENA.

of thunder. Radium, acting upon the atmosphere in contact
with it, or in its immediate vicinity, discharges the electricity
from certain molecules to certain other molecules, producing
miniature reactions. Possibly these miniature electrical dis-
charges produce light ; that is, one of these tiny flashes of light-
ning. Were our ears acute enough it might be possible to
distinguish these infinitely small claps of thunder.

The production of helium from radium is attributable not
to the conversion of any portion of the radium into helium, but
to the production of helium from the atmosphere or other me-
dium by the catalytic action of the radium. Therefore, the
energy does not come from the radium, but exists in the atmos-
phere as potential energy and is allowed by the radium to
become kinetic energy, just as the platinum causes sulphur
dioxide and oxygen at certain temperatures to combine, pro-
ducing heat.

From the observations made, Rutherford and Soddy1 sug-
gested that helium might be the production of the disintegra-
tion of the radio-active elements.

Gutton reported observations which, perhaps, have a bear-
ing upon the theory of radio-activity. He found that when
the lines of force of magnets are not parallel that luminous
effects may be produced upon a phosphorescent screen, de
Hemptinne,2 ho'wever, was unable to verify the observations.

Concerning the radio-activity of thorium, Baskerville3 has
called attention to the dividing of thorium into constituents
which differ in their activity. Hofmann and Zerban4 call at-
tention to the important fact, from a chemical point of view,
that thorium, which is radio-active, comes from minerals con-
taining uranium. All the thorium preparations, with which
physicists and chemists have usually worked, have, as a rule,
come from complex minerals which, probably, contained varia-
ble amounts of uranium. The above mentioned workers

T. Phil. Mag. (1902), 582; (1903), 453, 579-

2. C. R. 138, 754

3. J. A. C. S. 26, 922.

4- Berichte 35, 531, and 36, 3093.

THEORIES OF RADIO-ACTIVE PHENOMENA. 99

extracted from certain minerals, Norwegian gadolinite, yttro-ti-
tanite, and orthite free from uranium, thorium which did not
possess any radio-activity. Haitinger1 has succeeded in extract-
ing radium from thorium, which was prepared from Brazilian
monazite sands. The writer and Zerban have later obtained
a thorium preparation from a South American mineral, which
is absolutely inactive.

Fig. 45

Boltwood's apparatus for showing the ratio of radium to uranium in
minerals. A weighed quantity of powdered mineral is placed in bulb B.
The acid to be used for decomposing the mineral is placed in C. After
decomposition, which is brought about by inclining the tube so the acid
may come into contact with the mineral, the apparatus is allowed to
stand a few days until equilibrium is reached. The tube A is then sealed
off at e. The air and radium emanation are then remove 1 from A by
suction, introduced in an electroscope and the ionizing power determined.

Boltwood2 concluded from a determination of the amount
of radium in radio-active ore, and the rate of leakage of the
electroscope, that the amount of radium present stands in direct
proportion to the percentage of uranium.

1. Haitinger and Peters, Sitzungs Berichte (Wien) 113, May, 1904.

2. Eng. and Min. Jo urn. 77, 756.

ioo THEORIES OF RADIO-ACTIVE PHENOMENA.

It has been suggested by J. J. Thomson and Rutherford
as very probable that radium is formed by the breaking down
of the uranium atom. A final state of equilibrium and definite
proportion between uranium and radium present in minerals
was to be expected, which fact prompted Rutherford and
Soddy1 to suggest a complete study of the natural minerals.
The improbability of any radium ore being found containing
a greater portion of radium than pitchblende, because it con-
tains the highest percentage of uranium, suggests itself.

Preliminary experiments on the relative amounts of polo-
nium present in two different uranium minerals, showed by
comparison that in all probability this element also varies
directly with the percentage of uranium present.

Mendelejeff2 insists that radio-activity indicates a
material emanation. The arrival and departure of atoms are
accompanied by disturbances which indicate waves of light.

M. and Mme. Curie3 have presented a general theory con-
cerning radio-activity as follows : It is an atomic property.
Each atom acts as a constant source of emission of energy,
which may be derived directly from the potential energy of
the atom, or the atom may serve as a means whereby the energy
may be borrowed from the surrounding air. Crookes4 sug-
gested that radio-active elements possess the property of ab-
stracting energy from a gas. That is, in order to account for
the large emission of heat from radium noted by Curie and
Laborde, the moving materials might strike a substance and
be released with a changed lower velocity, a production of heat
resulting.

Lord Kelvin,5 also, suggested that radium perhaps obtains
its energy from an external source. It would Be interesting

1. Phil. Mag. 576.

2. "A Chemical Conception of the Ether," Longmans, Green &
Co., '04.

3. C. R. 134, 85, 1902.

4. C. R. 128, 176 (1899).

5. British Assoc., 1903 Meeting.

THEORIES OF RADIO-ACTIVE PHENOMENA. 101

to obtain inactive thorium and keep it for months in a vacuum
and note whether or not the de-emanated body re-acquired its
radio-activity.

Many are not as yet ready to accept the materiality of the
cathode or /2-rays. That the emanations are composed of defi-
nite particles is proved beyond question. Most active products
emit only a-ravs, or at least they constitute by far the major
portion of the radiations. No substance has yet been obtained
and known for any length of time which gives out only (3-
or y-rays, either alone or together. Rutherford states that
the ft- and y- rays in most cases appear only in the last stages
of radio-active processes. This statement must be modified
in view of the work reported by Rutherford at the Congress
of Arts and Sciences, St. Louis, 1904. (See end of chapter.)
Perhaps then in time those bodies which emit only a-rays may
yield the other two forms of recognized energy. Such falls
in well with the theory proposed by the writer1 and Lockhart,
which follows :

The elements of high atomic weight are electro-positive.
The emanation particles bearing a positive charge are repelled.
As they are lighter and gaseous, they are thrown away from
the ponderous solids at a high velocity, about i/io that of light.
These particles provoke an opposite charge producing ethereal
stresses, cathode or /3-rays. These acting upon any solid sub-
stance produce the y-rays in the same manner that the Rontgen
rays are produced without the Crookes tube through the influ-
ence of the cathode rays within. This 'appears to negate en-
tirely the postulates of Crookes and J. J. Thomson as to the
materiality of the cathode rays. It is maintained by some that
while the presence of material particles may be accepted, they
are the remnants of gas not removed in the exhaustion of the
tubes. In fact the efficient modern Crookes tubes for the pro-
duction of X-rays are arranged to keep a variable amount of
gas present within. The gas particles serve as carriers of the

i. "The Cause of Radio- Activity," Washington Section A. C. S., ,
April 6, 1904.

102 THEORIES OF RADIO-ACTIVE PHENOMENA.

negative charge and the assumption of the materiality of the
cathode or j3- rays becomes unnecessary.

J. A. McLennan1 stated that the emanation from radium
is not charged electrically. The radium atom gives off posi-
tively charged particles. "The emanation cannot be what
remains of the atom after the emission of these rays, as it
would then be negatively charged. The atom must have,
therefore, parted with an equal negative charge, either by the
emission of negative particles or in some other way."

Schenck2 proposed a theory for radio-activity based on the
hypothesis of electrons in phenomena of chemical equilibrium
and more particularly in that one between oxygen and ozone
which is controlled by the laws of mass effects.

Richartz has shown that ozone belongs to the group of
radio-active substances and on being dissociated will become
a conductor of electricity. In short, it would be converted
into oxygen while giving off gaseous ions. On the other hand,
its formation takes place whenever in certain electric phenom-
ena gaseous ions are present and a reversible process analo-
gous to the dissociation phenomenon occurs. If gaseous ions
be considered as material particles, the ozone may be regarded
as a chemical compound of electrons and oxygen, or an "elec-
tronide" of oxygen. Both electrons of atomical ions would be
controlled by the mass law in the same way as electrolytic ions
and electrical and neutral molecules. The hypothesis is sug-
gested that radium and analogous substances might also be
"electronides." The process might be analogous to the dis-
sociation of calcium carbonate into calcium oxide and carbon
dioxide. Probably radio-active substances should be produced
by volcanic phenomena, as they are attended by violent evolu-
tion of electricity. In many slow reactions giving rise to the
formation of ozone, the presence of gaseous ions has lately
been ascertained. It is probable that many, if not all, reac-
tions are attended with the presence of such gaseous ions in

1. Phil. Mag. 6, 7, 355 (1904).

2. Pruss. Acad. of Science (1904).

THEORIES OF RADIO-ACTIVE PHENOMENA. 103

variable quantities. On the other hand, hydrogen dioxide is
analogous to ozone, giving off so-called emanations which
do not influence photographic plates through a sheet of alumi-
num. It should equally be considered as an electronide. In
order to produce a luminous sensation on the eye, the concen-
tration of ions should apparently exceed a certain limit.
Schenck enunciates the hypothesis that emanations of radio-
active substances are nothing else than ozone. An attempt was
made to account for excited radio-activity by the action of
ozone.

Winkler1 took a rather radical position, insisting that all
of the reported radio-active elements simply contain a varia-
ble amount of radium, and furthermore he intimated that
radium itself is not an element but that it may be impure stron-
tium with an excessive electrical charge.

Davis,2 in endeavoring to decide between the two hypoth-
eses to explain radio-activity — namely, "Atomic Degradation"
and "Molecular Change" (Armstrong and Lowry, Proc. Roy,
Soc., 1903) — found that metallic selenium affected the photo-
graphic plate through black paper. Similar results have been
reported by Taudin and Chabot.3

McCoy4 discussed the decomposition of radium from the
standpoint of the law of mass. The order of decomposition
was considered as follows :

Ur —x Ur-X — x Ra — x RaEm — x Em-X — x He.
The radio-activity of an ore would be in proportion to all of
these, but may be judged by the amount of uranium present,
as was pointed out by Boltwood.3

Before giving the theories of those who have done most,
experimentally, (Rutherford and his co-workers), toward an

1. Berichte 37, 1655 (1904)-

2. Nature 70, 506 (1904).

3. Phys. Zeit, Aug. 25 (1904)-

4. Berichte 37, 2641 (1904).

5. Am. J. Sci. 1 8, 97 (1904).

IO4 THEORIES OF RADIO-ACTIVE PHENOMENA.

elucidation of the difficult problem, it is appropriate to mention
several interesting facts bearing upon the subject.

In 1895, Perrin,1 as did J. J. Thomson,2 two years later,
offered proof that the Crookes's rays consist of negatively
electrified material particles. Omitting the mathematical calcu-
lations, it may be said that these particles carrying a unit charge
are one ten-thousandth of a milligram'' in mass. Thomson
proved that the electric charge on a particle in case of gaseous
electrolysis is the same as that of a hydrogen atom in liquid
electrolysis; namely, 1.13 X io"20, E. M. U. and since the mass
of hydrogen required to carry a unit charge, in the case of
ordinary electrolysis, is one-tenth of a milligram, it follows
that the mass of cathode particles required to carry a unit
charge can be only one-thousandth as great. Therefore, the
masses of these electro-negative particles constituting the cath-
ode rays are one-thousandth of a mass of a hydrogen atom.
The accepted value of the mass of a hydrogen atom is 2.3 X
io"21, the mass of the cathode particles is 2.3 X io"24, milli-
grams. Thomson also determined the speed of the par-
ticles as being from 2.2 to 3.6 X io9 c.m. per second. The
speed of light is 3 X io10 c.m. per second. Hence the cathode
rays have a velocity of one-tenth of that of light. These veloc-
ities vary somewhat in different experiments, the highest value
obtained being about two-fifths the speed of light. Thomson
called the particles "corpuscles," as his ideas resembled New-
ton's corpuscular theory. In fact, Thomson suggests that they
constitute negative electricity, which is a return to the single
electric fluid theory of Franklin.4

The energy of the corpuscles is enormous. Although
they are minute, the energy effect is considerable. * It has been
estimated that the energy emitted from each square centimeter

1. Compt. Rend. 121, 1130.

2. Phil. Mag. V, 44, 293.

3. Phil. Mag. V, 48, 547 (1898).

4- Harper's Magazine, 103, 64, Sept. (1901).

THEORIES OF RADIO-ACTIVE PHENOMENA.

105

of radium would melt a layer of ice of the same area and one-
quarter of a mile thick in a million years. Or, as Lord Kelvin
has said, the emission of matter and corresponding- loss of
energy have apparently been going on indefinitely in the past.
As he says, it appears to place the first question mark after
the great fundamental law of the conservation of energy.

Strutt devised an instrument which gives the nearest ap-
proximation to perpetual motion so far observed. The descrip-
tion of a radium clock as constructed by Mr. Harrison Mar-
tindale of England is given as illustrative of the principle of
Strutt's apparatus. The registration of time is made in two-
minute beats. The function of the apparatus is to exhibit the
dissipation of negatively charged a- and /3-rays by radium.
A small tube containing a minute quantity of radium is sup-
ported in an exhausted glass vessel by a quartz rod. To the
lower end of the tube is attached an electroscope formed by
two strips of silver foil. The leaves diverge, striking the walls

Fig. 46.

Strutt's Radium Clock. It has been suggested that a very reliable
time-piece may be constructed on this principle. So far however no
satisfactory method of mechanically registering the charging and dis-
charging, that is, beats, has been devised.

io6 THEORIES OF RADIO-ACTIVE PHENOMENA.

of the vessel, which are grounded by wires, and are discharged.
The operation is repeated incessantly requiring two minutes.
In this instance it is calculated that it will take 30,000 years
until the radium is exhausted.

The speed with which the corpuscles move from the radio-
active substances is even greater than that of Crookes's rays,
Becquerel has shown that their speed may be as high as two-
thirds that of light. Other investigators have obtained even
higher velocities, 2.8 X io'° c.m., having been measured. The
rays emitted by radio-active substances consist in part at least
of material particles having a high velocity. Therefore, a loss
of matter must go on continuously. Madame Curie estimates
that radium emits from each square centimeter of surface 1.2
milligrams of matter in one million years. Therefore, it would
be impossible to observe, by the most delicate balances at pres-
ent available, any loss in mass during two million years.

Two important questions present themselves to the reader
if these statements even approximate the truth. Where does
this radium and radio-activity come from? and what is its real
influence in the world ?

W. E. Wilson,1 Darwin2 and Joly3 independently suggested
that radium might enter as an important factor in contributing
to solar radiation and the maintenance of solar temperature.
Reference has already been made to Rutherford's belief that the
amount of radium present and uniformly distributed through-
out the earth would be sufficient to account for its loss of heat.
Thus it will be seen that .the life of the earth has continued
sufficiently long to allow the time necessary for the processes of
evolution of the geologists and biologists.

Thomson, at a recent meeting of the British* Association,
as a result of his experiments on the universal distribution of
radio-activity, concluded that each metal gives out a specific
radiation which differs in its properties from the radiations sent

1. Nature, July 9 (1903).

2. Nature, Sept. 24 (1903).

3. Nature, Oct. i (1903).

THEORIES OF RADIO-ACTIVE PHENOMENA. 107

out by any other substance, and appears not to be a secondary
radiation due to contact with some other form of radiation
present in the atmosphere.

So far no satisfactory experimental evidence has been
offered to prove that the energy of radium is derived from
external sources. Yet the following idea gave the writer
momentary comfort. An insulated wire formed into a circle,
the ends free, horizontal, vertical, or inclined as far as the
earth's surface is concerned, is perfectly neutral. Let it be
revolved and an electric current is produced. Evidences of
energy are had. Vary the speed and number of circles and
differences in the current are observed.

Is it too great a draught upon the imagination to think
that the atoms which are heaviest possess this same power?
Their motion, perhaps on account of their weight, is such as
converts the earth's lines of force into perceptible energy.
The Curies early made a suggestion somewhat similar to this;
namely, that radium might have the power of absorbing a
species of Rontgen rays from the earth and converting them
into other forms of energy. It has been shown that there is
in fact a kind of penetrating rays, like the y-rays of radium,
near the earth's surface. The writer's dream was dissipated
by rinding a heavy constituent, inactive thorium. It comes
back now, since Rutherford has shown that during the disin-
tegration of the emanation a temporary inactive state is arrived
at.

So substances may vary in the amount of their activity,
as shown for radium and thorium preparations. Fresh radium
requires time to reach its maximum. So does thorium, while
Rutherford's thorium-X runs down to a minimum, which
is the maximum of its mother substance. In one case it re-
quires time to reach the stable speed. In the other, it requires
time to slow down to the safe equilibrium rate. The dynamo
analogy becomes more perfect when we have active and inac-
tive thorium.

io8 THEORIES OF RADIO-ACTIVE PHENOMENA.

J. A. Alexander1 insists that radio-activity is due to exter-
nal energy. He says :

"All matter, as we know, is continually receiving and
giving out energy but the total sum of the plus and the minus
in the universe equals zero.

Radio-activity and magnetism are in some respects anal-
ogous. Each is exhibited most strongly by one element, and
to a lesser degree by several closely allied elements. Each can
be communicated to some other bodies without apparent loss
to the original active substance. Both are impaired by heat,
fusion or solution, which seem to alter the conditions of the
molecular complexes. We believe magnetism to be consequent
upon the localization of ever-existent cosmic forces ; and it
seems to be probable that radio-activity can be traced to the
same origin."

Rutherford and Soddy, assuming that radio-activity is an
atomic and not a molecular property, advance the most accept-
able theory yet put forward ; namely, the atoms of radio-active
elements undergo spontaneous disintegration. This takes
place in fixed and well-marked steps. These changes are
nearly always accompanied by the emission of a- rays.

The emission of the radiations is dependent solely upon
the amount of active element present. The rate of emission is
not affected by- variations in temperature or by any known
chemical or physical forces. It has been demonstrated that
the radiations consist for the most part of positively and nega-
tively charged particles, projected with great velocity. Hence
it has been assumed that part of the atoms escape from the
atomic system. It is difficult to imagine that the projected
particles can suddenly acquire such a velocity of movement
through the action of force, either within or without the atom.
To illustrate this point, attention may be called to the fact
that the a particles, according. to Rutherford, ''would have to
travel from rest between two points, differing in potential 5.2
million volts, in order to acquire the kinetic energy with which

i. American Chem. Society (N. Y. Sect.), Nov. n, 1904.

THEORIES OF RADIO-ACTIVE PHENOMENA.

109

it escapes. They must, therefore, escape from a system which
is already in exceedingly rapid motion. Consequently, the
energy exists before hand in the atoms from which they
escape."

J. J. Thomson, Larmor and Lorentz have urged the con-
ception that the atom is very complicated, being made up of
charged particles, in rapid oscillatory or orbital motion. As
the particle is atomic in size, it must be composed of electrons
in motion. The radio-active elements, therefore, are composed
of positively charged particles, whose mass is about that of
hydrogen or helium.

12
DAYS

Fjg. 4y— CURVES SHOWING DECAY OF ACTIVITY OF THE

EMANATION AND RECOVERY OF ACTIVITY OF

RADIUM (AFTER RUTHERFORD).

The curves (see Fig. 47), showing the decay of the activ-
ity of the emanation and the recovery of the activity of radium
are extremely interesting. It will be noted that they are com-
plementary to each other. When the emanation has lost one-
half of its activity, the radium has spontaneously regained one-
half of its lost activity. The sum of the three factors, namely
the activity from the separated emanation, the activity of the
remaining radium, and that lost, constitute a constant. This

no THEORIES OF RADIO-ACTIVE PHENOMENA.

is accounted for by assuming that radium is always manufac-
turing fresh emanations at a definite rate. When the emana-
tion is removed, the radium is temporarily exhausted but imme-
diately proceeds to produce more emanation and store it up.
As these two reach an equilibrium, we have the constant activ-
ity of the radium.

The laws which control the material a and /? particles
are different from those of ordinary chemical changes. Tem-
perature, which plays an important part with all ordinary
chemical reactions, has no noticeable effect in changing the
processes occurring in radium, as already referred to. The
rate of decay of the activity of the emanation is apparently
not changed by severe physical and chemical treatment. As-
suming that changes occur within the atom, we should expect
temperature to have little influence, for we know from our
experience with different elements that wide variations in tem-
perature have little effect in altering stability. During this
process of disintegration at least five distinct substances are
produced. The emanation is, chemically, an inert gas, while
the other products act like metallic substances — soluble in some
acids and volatilized by heat. Each of these different sub-
stances is different from an ordinary chemical element, because
it is not permanent and is continuously and rapidly changed
into another kind of material. This is shown graphically by
Rutherford in the accompanying diagram (Fig 48). Ruth-
^.erford gives a very interesting table showing the time required
for the different changes.

Fig. 48.— DIAGRAM TO REPRESENT THE DISINTEGRATION
OF A RADIUM ATOM (AFTER RUTHERFORD)

THEORIES OF RADIO-ACTIVE PHENOMENA.

Name of Substance

Time

Remarks

Radium

Emanation

4 days

Jst product

Emanation X (ist change)

3 minutes

2nd product

Emanation X (2nd change

21 minutes

3rd product

Emanation X (3rd change)

28 minutes

4th product

Emanation X (4th change)

very slow

5th product

In each case, but one, the transformation is accompanied
by the throwing out of a particles and in one only, namely
the fourth stage, are evidences of ft- and y-rays obtained. Some
evidence is already had which indicates that radio-tellurium is
really the fifth product of the disintegration of the radium atom.

Each one of these chemical products has distinct chemical
properties, which distinguish it, not only from its immediate
neighbors but from the parent element and the final product.

It has been calculated that the weight of the emanation
obtained within four days from one gram of radium bromide
is about i/ioo of a milligram, while the weight of the fourth
product, which breaks up in twenty-eight minutes, is about
3/100,000 of a milligram. This amount is entirely too small
to be detected by balances, so it can scarcely be hoped that
enough of it can ever be collected, in sufficient quantity, on
account of its limited life. The inactive products, however,
will continue to increase as long as there is any of the mother
element present. This is really an apparent case of the trans-
mutation of the elements.

Truly, as Runge says, "Nature is becoming more and more
disorderly every day."

In the author's humble opinion we are not yet warranted
in accepting this as the correct solution of the problem, beauti-
ful as the explanation is. So far, however, nothing better has
been offered and, as with all things in science, it should be
accepted until something better takes its place.

H2 THEORIES OF RADIO-ACTIVE PHENOMENA.

Ramsay1 states that electrons are not matter but are capa-
ble of causing profound changes in matter. For a year a solu-
tion of radium bromide was kept in three glass bulbs, each
bulb connected to a Topler pump by means of capillary tubing.
This was done to collect e.v-radio, the term he proposed for
"emanation-substance." Each of the bulbs, to avoid accident,
was surrounded by a small beaker, one consisting of potash
glass and the other two of soda. The potash beaker became
brown, while the two soda beakers became purple. This varia-
tion in the color was attributed to the probable liberation of the
metals potassium and sodium, which ordinarily exist in that
very viscous liquid, glass, in the colorless ionic state. The glass
had not been subjected to the a-rays, therefore, to no bombard-
ment of what is usually called matter except the molecules of the
surrounding air. The colored beakers are radio-active and
the radio-active film dissolves in water. After careful washing
the glass was no longer radio-active. The solution contained
an emanation, for in bubbling air through it and cooling the
issuing gas to — 180° C, part of the radio-active matter was
retained in the cooled tube. This air, also, discharged an elec-
troscope. The period of decay was very rapid. In having
such a short period of existence the emanation resembles that
of actinium. The water solution on evaporation gave a resi-
due which was strongly active. On adding mercurous nitrate
to the dissolved residue and then adding hydrochloric acid
the greater part of the active matter was thrown down with
the mercurous chloride. This appears to indicate the forma-
tion of an insoluble chloride. The activity of the mercurous
chloride remained unchanged for ten days. The filtrate from
the mercurous chloride was active. On precipitation the mer-
curous sulphide was also active but its activity decayed in one
day. The filtrate from that gave an inactive precipitate with
ammonium hydroxide, hence the active matter forms an insol-
uble chloride and sulphide. These, when dissolved in aqua

i. "Present Problems of Inorganic Chemistry," address before the
International Congress of Arts and Science, St. Louis, 1904.

THEORIES OF RADIO-ACTIVE PHENOMENA. .113

regia, gave an insoluble sulphate when barium chloride and
sulphuric acid were added. This indicates the formation of
an insoluble sulphate, that is a body somewhat resembling lead.
The explanation given for this was perhaps misinterpreted by
the secular press into the actual building up of elements ; in
short, a verification of the dream of the Alchemists, although
Ramsay gave as his "guess" that such an explanation was more
than likely.

Without doubt the most valuable of the recent work on
the "Transformation Products of Radium" was that reported
by Rutherford1 at the International Congress at St. Louis. He
studied the residual activity of a bismuth rod exposed to the
emanations of radium. The residual activity consists of both
a- and /3-rays, the latter being present in unusually large pro-
portion. He, also, noted the proportion of the a- to (3- rays-
from a platinum plate one month after removal from exposure-
to the emanations. Unlike the a- rays activity, the activity meas-
ured by the ft- rays remains constant, consequently the propor-
tion of the a- to the (3- rays steadily increases. The intensity
of the /8-rays did not vary much over a period of nine months.
This want of proportionality between the a- and /3-rays shows
that the two types arise from different products. The activity
deposited apparently consists of two kinds of matter: (i) a
product giving only /8-rays which is soluble in sulphuric acid
but not volatile at 1000° and which is not deposited on bismuth ;
and (2) a product giving out only a- rays which is soluble in
sulphuric acid, volatile at 1000°, and is deposited from a solu-
tion on bismuth.

The a- ray activity increases if the ft- ray product is pres-
ent. It remains sensibly constant, or generally very slow in
decay, if the a- ray product is removed from the /8-ray product
by the action of the bismuth plate. The /3-ray activity remains
sensibly constant independent of the presence of the a- rays.
These results show that the /3-ray product is the parent of the
a- ray product. The amount of residual activity from radium

i. Phil. Mag. 8, 636 (1904).

ii4 THEORIES OF RADIO-ACTIVE PHENOMENA.

MASS VELOCITY ENERGY

—

•

Fig. 49. — A graphic comparison of the a and /? particles. The velocity is
represented by the length of a line and the mass and energy by spheres.

emanations depends upon the amount of the emanation present
and the time of exposure to the emanation. Rutherford has
changed his nomenclature and illustrates graphically the
change, as shown in Fig. 50. By such an explanation he is
able to account for the presence of radium-D and radium-E
in pitchblende. He doubts if radium-D has been separated
from pitchblende, although it is barely possible that the radio-
lead of Hofmann, which emits a large amount of /?-rays, may
be radium-D. Concerning radium-E, he thinks there is little
doubt that it is the radio-tellurium of Marckwald, as his active
bismuth gave out only a-rays. Rutherford states that it will
be of extreme scientific value if the radium-D can be had from
pitchblende, as it could be used for many of the purposes of
radium. Its activity is about 25 times that of radium and the
rate of change in the activity is sufficiently slow to be negligi-
ble for most experiments.

apt.

Radium

Active Deposit

of
Ropid Change

Fig- 50

Active Deposit
Slow Change

Diagrammatic representation of the changes occurring in radium and
its emanations according to Rutherford [Phil., Mag. 8, 641 (1904).]

CHAPTER VI.

THE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE

SUBSTANCES AND THEIR THERAPEUTIC

APPLICATIONS.

From what we have learned in the preceding chapter as
to the resemblances among the radium and other rays, it is
not unreasonable to anticipate specific physiological effects
from the radio-active substances. That this is true, however,
was accidentally and painfully discovered previous to the
observation of WalkhofP that radium rays inflame the skin
similar to the Rontgen rays.

Becquerel carried a small tube of an impure radium prep-
aration in~his vest pocket for six hours. A few days later he
observed a reddening of the epidermis of the abdomen opposite
the location of the pocket in which he had placed the radium
compound. It was not long before the inflammation became
pronounced, and an ulcer developed which required several
months for the healing.

Giesel2 exposed the inner portion of his arm, for two
hours, to 0.27 gram of a radium preparation, enclosed with a
double celluloid capsule. After two or three weeks the skin
reddened, blisters formed and the epidermis peeled just as with
a burn. The growth of hair was also destroyed and did not
come out anew, although a smooth white skin reformed. These
observations were verified by Becquerel and Curie. "The
action of radium upon the skin can take place across metal
screens, but with weakened effect."3 (Fig. 51.)

1. Photogr. Rundschau, Oct., 1900.

2. Ber. d. deutsch chem. Ges. 33, 3570 (1901).

3. Madame Curie's Thesis.

PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

Fig- 51-

Professor Curie's arm, showing a scar resulting from a radium
sore. (Through the courtesy of the Success Company.)

Rehns studied the precise effect of radium burning upon
the skin. The rays from twenty milligrams produced no pain
and left no mark at the time of the application. A red mark
appeared 24 hours later, remaining for two weeks and then
fading away, leaving a scar similar to a burn. If the applica-
tion be continued for ten minutes the mark becomes visible
in 1 8 hours, but ulceration does not occur unless the radium
has been applied for at least an hour. If the burned spot be
treated medicinally the wound may be cured in six weeks, but
if not attended to, it ulcerates, becomes painful and the ulcer-
ation lasts for an indefinite period.

* Moles can be destroyed by the application of radium for
ten minutes.

i Abbe1 appears to have been the first to record the fact that
an ordinary wart (verruca vulgaris) is caused to disappear by
the application of radium. The age of the growth seems to
have no influence. Within three or four days a pink zone
appears around the base of the growth, then it begins to flatten
and usually disappears inside of ten days, leaving a smooth
skin.

Giesel observed the action of radium upon plant growth,
noting that the leaves treated turned yellow and withered
away. He, also, discovered the action of radium upon the
eye. If a radio-active substance be placed near the eye or

i. Medical Record, 66, 321 (1004).

AND THEIR THERAPEUTIC APPLICATIONS. 117

temple, when the person is in the dark, a sensation of light
is experienced. On the announcement of these observations
the secular press hailed a cure for blindness. Heinstadt and
Nagel and Crzellitzer, however, have studied the phenomena
carefully and demonstrated that the centre of the eye is ren-
dered fluorescent by the action of the radium. This gives
the sensation of light experienced.

The effect upon the eyes produced by radium is a diffuse
brightness, somewhat like that one experiences when he steps
from a dark to a brilliantly lighted room, with the eyes slightly
closed, that is, the interior of the eye begins to fluoresce. The
cornea, the lens, especially the vitreous humor, and perhaps
the retina are involved. This is quite different from the
effect of Rontgen rays, which act upon the retina alone. A
pure radium salt acts with such intensity that the effect may
be obtained by placing the chemical back of the head, and
without the intervention of the optical apparatus at all. The
Becquerel rays may produce an apparition, but it is not pos-
sible to secure a picture as they are deficient in a characteristic
property of visible light, namely, refraction.*

Concerning the statement that totally blind persons are not
only able to see the radium light, but perceive the phosphor-
escent radium screen and distinguish silhouettes, coins, keys,
etc., placed on the screen, Halzknecht and Schwarz2 offered
two explanations. The radium rays passing through the tis-
sues reach and irritate the optic nerve and stimulate the relics
of visual capacity left in it. In this case the nerve would
also experience the same tendency. The blind person, after
a little practice, should be able to perceive any dark object
on a bright background. Heller, having made some experi-
ments along this line, found it possible and that the same
results could be obtained by any light. The radium had

1. See Karewski in Marckwald's "Uber Becquerelstrahlen und
radio-active Substanzen," Moderne Arztliche Bibliothek, Heft 7, Berlin
(1904).

2. "Ueber Radium-strahlen," Wien Klin. Wochenschrift 16, 25.

PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

nothing specific to do with the phenomenon. The other and
perhaps the correct explanation, is based upon the transforma-
tion of the energy of the radium rays into objective phosphor-
escence. Animal tissue, hair, bone, muscle, drops of water,
etc., are rendered more or less vividly phosphorescent under
the action of the radium rays. The radium rays render the
sclerotic phosphorescent and this phosphorescence is seen by
the point of the retina opposite to it. When a visual sensation
is experienced from compression of the eye-ball, the source
of the light is referred to the point opposite to that from
which the compression light proceeds. This is the reverse of
the experience with radium.

There is no doubt but that blind people whose retinas are
intact are sensitive to the action of radium, but those with
diseased retina experience absolutely no luminous sensation.
London, in St. Petersburg, aroused many hopes by his observa-
tions, but GreefF, in Berlin, on extending the experiments,
came to the same conclusions given above.

— Javal1 has suggested that blindness with alteration of the
retina can be distinguished from that due to glaucoma or
cornea! opacity, because patients with the latter condition see
radium rays as well as do those of sound vision.

Rollins2 suggested the use of radio-active substances as
a substitute for "the X-light. He prepared a capsule, with an
aluminum front and back of comparatively non-radiable metal
hich could be worn over a lupus or superficial cancer.

Danlos3 of the St'. Louis Hospital, Paris, apparently was
the first to apply radium in the treatment of certain affections
of the skin similar to the treatment with Rontgen and the
ultra-violet rays (Finsen). A case of lupus of the face was

1. Revue Internationale d'Electrotherapie et de Radiotherapie, Nov.
and Dec., 1902.

2. Medical News, Jan. 25 (1902).

3. Revue 1'Electrotherapie et Radiotherapie, Nov. and Dec. (1902).
Ann de Dermatologie et de Syphilis, July (1902).

AND THEIR THERAPEUTIC APPLICATIONS. 119

treated with radium chloride (iQOOoX). The disease disap-
peared with the formation of a smooth white cicatrix, blending
into the surrounding tissue.

Fig. 52.

Dr. Danlos and assistants treating a lupus patient with radium.
(By courtesy of the Success Company.)

Hallopeau and Gadaud1 report that too prolonged applica-
tion of radium led to atonic ulceration which lasted for five
or six months ; also, that ulcers of normal tissue can be avoided
by proper technique and care.

Blandamaur has also used radium in lupus.

Danycz2 found that radium destroys the skin of guinea pigs
and rabbits ; but subcutaneous and muscular tissue do not seem
so sensitive as skin. Nervous tissue is sensitive to its action.
A glass tube containing a radium salt, which was placed against
the skin over the spine, produced death in young animals. In
older animals, the osseous tissue seems to protect the cord

1. Ibid.

2. Compt. Rend. 136, 461 (1903).

i2oTHE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

against the radiations. Danycz and Bohm showed that various
larvae and embryos are profoundly modified in their growth,
many being killed, when subjected to the radiations; others
developing into monstrosities, because of unequal stimulation.
The latter1 observer found that the radiations exercise an espec-
ially intense action on tissues and cells in proliferation. Non-
fertilized eggs may undergo more or less parthenogenetic de-
velopment and give rise to atypical formation. In the case
of some animals, where the skin has been burned by the rays,
the hair appears to be forced into rapid growth. It seems that
various effects are obtainable, depending on the tissue or cell
exposed, as well as on the quantity and quality of the rays.

When two groups of meal worms were placed in jars, oveV
one of which radium was suspended, many of the radiumized
worms died ; those which lived showed much retardation. The
worms in the 'parallel jar passed through the regular cycle of
life, laid eggs which grew to worms, and repeated the cycle
three or four generations. The radiumized worms still
remained mere worms.

B6hmv reported, as a result of experiments, that lower
organisms are quickly destroyed by radium rays.

Tur exposed eggs, for 24 to 70 hours, to the action of a
35 per cent, radium chloride. The central parts were partic-
ularly affected, t-he surrounding blastoderms remaining un-
touched. Aside from numerous variations in the embryonic
skeleton, there was a peculiar vascular formation in the centre
of the embryo and other phenomena, showing a peculiar local-
ization of the injurious radio-active effects.

Holzknecht3 reported psoriasis and lupus hypertrophicus
as cured by both X-rays arid radium. The radium was superior,
if anything. Epithelioma of the cheek also rapidly sub-
sided. Apparently the healthy skin in the neighborhood of

1. Compt. Rend. 136, 1016 and 1085.

2. Soc Biol 55, 1655.

3. Wirkung der Radiumstrahlung bei Hautkrauheiten, Vienna Klin
Wochenschrift, 16, 27 (1903).

AND THEIR THERAPEUTIC APPLICATIONS. 121

these affections is not seriously interfered with. Radium
seems to produce degenerative processes in the cells of the
intima of the blood vessels, shown by Scholtz, as character-
istic of the Rontgen rays. On account of the degeneration,
there ensues a rapid dilatation of the capillary and precapillary
vessels. These observations were made upon a remarkable
case of telangiectesis.

A committee appointed by the Vienna Academy of Science
to investigate the results of the treatment of cancer with
radium, reported, says the Popular Science Monthly, "in nine
cases in which the treatment was used abatement in the can-
cerous swelling resulted, and in two of these cases the swelling
had not reappeared after five months' time. A case of cancer
of the palate was much improved by the treatment. The use
of radium is not recommended when an operation is practica-
ble." Numerous other cases of the beneficial results of the
radium treatment have been reported. The press reports from
the London Cancer Hospital do not appear to be so encour-
aging.

Exner1 applied a capsule containing a cadium preparation
by fastening it to the spot with adhesive plaster. The nodules
following an operated melano-sarcoma disappeared when
treated twenty-five minutes with the radium. They disap-
peared before the superficial tissues exhibited necrosis from
the action of the rays. A capsule containing radium bromide,
protected from moisture by a rubber cot, was applied to a case
of epithelioma, at the corner of the mouth, six times within
seventeen days. The tumor perceptibly diminished, the ulcer
began to heal over ; at the end of the month it had apparently
vanished. This physician also reports on the radium treat-
ment of six cases of carcinoma of the oesophagus.2

The technique was the introduction of a scrap of radium
embedded in dammar, and fastened to a No. 16 sound. The

1. Radium Treatment of Malignant Tumors and Cutaneous Affec-
tions; Vienna Klin Wochenschrift 16, 27 (1903)-

2. Semaine Medicale. Paris, 24, 9 (1904).

I22THK PHYSIOLOGICAL ACTION OF RADIO-ACTIVF SUBSTANCES

increased permeability of the structure noted in the five cases
was probably due to necrosis of the structure tissue under the
influence of the radium, thus giving permanent results.

Morton1 favors radiation to* operation in the treatment of
malignant disease in its earlier stages. Robert Abbe2 sum-
marized his wide experience with radium in the treatment of

ADJUSTABLE
METALSUPPORT

•, \m/.--.

ADJUSTABLE
I METAL SUPPORT

G>ASS CUP

Figs. 53 and 54.

Method of applying radium preparations in local treatment accord-
ing to Morton.

lupus, epithelioma, rodent ulcer and carcinoma, by saying "lupus
can usually be cured by a few applications of radium, varying in
number, and frequently with the strength of the specimen.
Superficial epithelioma, rodent ulcer, and small recurrent can-
cer nodules, can be caused to disappear by cautio'us applica-
tion, but if mild preparations are used, very little effect is seen.
Indeed, the judicious use of Rontgen rays is more efficient
along the same line in results and with only brief applications."

1. "Treatment of Cancer by the X-rays with Remarks on the Use
of Radium;" International Journ. of Surgery, New York, Oct. (1903).

2. Yale Medical Journal, June (1904).

AND THEIR THERAPEUTIC APPLICATIONS.
HOLDER

123

Fig- 55-

Apparatus of Williams, Brown & Earle, used in applying radium
compounds in medicine.

Seventy-five milligrams of radium, in a mica-covered box,
were bound to Goldberg's1 arm for three hours. Four days
later a red patch developed, changed into a necrotic ulcer on
the fourteenth day, and other ulcers developed on different
parts of the arm; also, on the skin, in the groin and hand.
The healing processes commenced first in the later patches.
The ulcers were slow but sure in the healing. The action of
the radium was probably due to its activity and not to its bulk.
The exposure and the subsequent phenomena were painless.
The necrosis developed without fever, and the ulcer had a
peculiar morbid character. Rodent ulcers were cured.

Cleaves2 reports the cure of several cases of recurrent
epithelioma of the rodent ulcer type.

Williams, who has carried out most systematic investiga-
tions on the medicinal applications of radium compounds, calls

1. "Zur Frage der Beziehungen zwischen Becquerelstrahlen., und
Hautaffektionen," Goldberg and London, Dermatologische Zeitschrift,
Berlin, 10, 5 (1904).

2. i3th Ann. Meet. Amer. Electro-Therap. Assoc., Atlantic City,
Sept. 24, 1903.

124 THE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

attention to the fact that radium possesses less value in diag-
nosis than X-rays, as it does not differentiate so clearly. He

Figs 56 and 57.

The simple technique of applying radium compounds in the treat-
ment of skin diseases.

employed it as a therapeutic agent in nine cases of skin affec-
tions, two of eczerna, and psoriasis, four of lupus vulgaris, and
one of acne. Success was not so good in eczema, although
there was some improvement. In lupus, the results were sat-
isfactory ; also with acne. This important paper has reference
to other work, which treats of thirty-three cases which show
that radium is useful in treating some skin diseases and super-
ficial new growths, including in this class those of the cervix
uteri. He endeavored to differentiate as to the value of the
different rays by isolating the ft and y rays. The burning
power he attributes to the /3 rather than the y rays. As a
result of his large experience, he regards the therapeutic ac-
tion of radium as being of greater value than the X-rays, ex-
cepting that the latter is able to cover larger areas. He con-
cludes as follows : "If the results obtained by radium prove

AND THEIR THERAPEUTIC APPLICATIONS.

125

xn.

Fig. 58

Lieber's Aluminum Tube for containing Radium.
A. — Aluminum tube containing radium, which is closed hermetically
by

B. — a wedge fitted with a screw thread so that

C. — a lid may be screwed on same, thereby closing the tube her-
metically. This must not be opened after the radium has
been filled in.

The lid C has a screw thread on which may be fastened

D. — a silver mantel or cover, which can be removed at will, or in

which holes or windows of any desirable size may be cut,

such as indicated in E, to permit the escape of all radiations.

F. — is a short silver mantel which is to be used to produce a smooth,
ending surface by attaching same to C when the long silver
mantel D is not to be used.

G. — is one of the great variety of handles which may be readily at-
tached to B.

There is also furnished a small plug, which has on its
lower end a screw thread, which will fit readily in B. To
this plug may be attached thin rubber hose: Catheters,
Bougies, etc., to answer any purpose.

I26THE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

permanent this new therapeutic agent will be largely used
instead of the X-rays ; but the two will supplement each other.
Certain diseases promise to yield more readily to treatment
by radium, and other diseases more readily to X-rays. A dis-
ease that has attacked different parts of the body of a given
patient may be better treated in certain regions by radium, and
in others by the X-rays, and it is quite possible that in some
cases the two remedies used together on the same area, and
at the same sitting may accomplish better results than either
alone."1

Fig. 59

This shows an epithelial cancer of the ear, before and after treat-
ment by radium. The disease remained cured after one year. (Robert
Abbe in Medical Record, 66, 321, 1904.)

Truman Abbe2 remarks, "The radium rays, -no doubt,
should be classed with the X-rays, the Coley serum, Adamkie-
wicz serum, and the various caustics. These have given cures

1. "Some Physical Properties and Medical Uses of Radium Salts ;
with a Report of Forty-two Cases Treated by Pure Radium Bromide,"
F. H. Williams, Med. News. New York, Feb. 6 (1904).

2. Washington Med. Ann. 2, 363 (1904).

AND THEIR THERAPEUTIC APPLICATIONS. 127

in a few cases of inoperable and malignant diseases, but they
are far too uncertain to be used except when operation is out
of the question."

Lyster, of the Middlesex Hospital, uses radium of low
activity and pitchblende. He applies pitchblende directly to
the diseased structure for twenty-four hours, binding it on.
The radium is permitted to excite only the granulations.

At the Cancer Hospital, London, radium is used in an ap-
paratus made of ebonite with a quartz shield. To condense
the radiations the shield is held against the ulcer.

Maclntyre1 applied radium by enclosing it in a small cell
with a mica face. This was surrounded with a small piece of
India rubber tube which fitted into the apex of a glass cone.
This localized the action of the radium to the particular part
to which it was applied.

According to Robarts2 the treatment is done through a
rubber pocket. He remarks : "It has been observed that higher
activity gives better results than lower activity."

David MacKenzie'5 does not claim for radium any special
value over the X-rays. Phimosis scytitis is increased and ruga
scytitis varies, being increased within the neighboring walls
of the vessels. He also reports the curing of rodent ulcer,
tuberculosis, verucca, cutitis, rodent cancer and the disintegra-
tion of moles. Fragmentation of the covering of coloring
matter was observed, as after X-ray treatment. The effect
ot radium is more rapid than that of the Rontgen rays ; that
is, a tissue reaction is quicker. He, also, states the method
of application as used ; that radium was not used in carcinoma ;
and suggests the possibility of applying thorium in large quan-
tities to septic ulcers.

Sichel4 applied five milligrams of radium bromide forty-
two times to rodent ulcer with success.

1. British Medical Journal, June 6, July 25 (1903).

2. American Journal Surgery and Gynecology.

3- British Medical Journal, Jan. 22 (1904).

4- British Medical Journal, Jan. 23 (1904).

I28THE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

Apolant1 studied the retrogression of carcinoma on mice
under the influence of radium rays. The carcinoma cells van-
ished and there was proliferation of the connective tissue. In
addition to the destructive action, it appeared to induce spe-
cific absorption of dying carcinoma cells. He remarked that the
loss of penetrative power imposed such a limit to the effect of
the radium treatment, that it has rendered it dubious whether
as a therapeutic agent, it has much of a future.

Pozzi and Zimniern* reported an improvement in the case
of cancer by treatment with radium. They, also, called atten-
tion to the necessity of determining the extent of the dosage.

Darier3 noted the rapid and penetrative analgesic action
of radium in certain cases of cyclitis and irido cyclitis. Prepara-
tions of low intensity were often capable of rapidly removing
pain. In two cases of convulsive neuralgia, which came on
frequently, the attacks ceased after a few applications of radium
to the temple for two or three days. Radium effected a cure
of an acute facial paralysis of recent origin.

Foveau de Courmelles* found by local application of
radium chloride that the pain from facial neuralgia or cancer
could be alleviated. He reports, also, that a plaster of thorium
oxide may be successfully applied in the shape of a sort of
varnish and the powder may be wrapped in tin foil and applied
to the face. The. successful treatment of several severe cases
of neuralgia were reported.

Pusey5 gives an excellent resume of the therapeutic possi-
bilities of radium. Concerning its effects upon the nervous
system he ,says, "The symptoms are first depression of the cen-
tral nervous system followed by flexures of the cerebro-spinal
system. The explanation of these nervous symptoms lies in the

i. Deutsche Mediciniche Wochenschrift (1904).
2,. Medecine Moderne, July 6 (1904).

3. Lancet, March 5 (1904) ; Paper presented before the French
Academy of Medicine, Feb. 16 (1904).

4. Progres Med., May 28 (1904). See also his book on the subject..

5. Journ. A. Med. Assoc., July 16 (1904).

AND THEIR THERAPEUTIC APPLICATIONS. 129

disintegration of the nerve cells produced by the Becquerel
rays. The Becquerel rays affect at the same time the skin,
epithelium, connective tissue and blood vessels. The effect on
the last named appears first."

Holkin,1 in a very thorough study of the action of the
Becquerel rays upon the skin, noted the cellular degeneration
and dilatation of the vessels in normal as well as in lupus tissue.
The changes appeared only in the most superficial layers of
skin.

From a comparison of Holkin's work and studies of
Scholz on X-ray burns in young pigs, it is quite evident that
the action of the two agree very closely, and may be said to be
identical, with the single difference of the greater depth of
action of the X-rays. The cells of neoplasm are as susceptible
as new cells produced by irritation to the effects of the Bec-
querel rays, but they are of lower resistance, consequently their
structure is disintegrated and they degenerate before the irri-
tant cells are so violently affected.

Pusey insists that radium "will have a definite, though a
limited field of usefulness in the treatment of regions situated
in inaccessible locations, where it is difficult or impossible to
apply the X-rays, but where radiations from radium can be
applied readily." He reports its application on carcinoma of
the uterus, rectum and mouth. He reports no definite effect
from the use of thorium nitrate and oxide.

Schamberg2 directs attention to the decided difference in
the susceptibility of different individual radiations.

Bulkley3 reported in one case of lupus better effects from
the X-rays than with- radium. He applied it successfully in
case of epithelioma, beneath the tongue and to the tonsil. Treat-
ment by surgical means would have been difficult. The disease
disappeared gradually under the influence of the radium.

1. Archiv f. Dermatologie und Syphilis, 65 (1903).

2. Journ. A. Med. Assoc., July 16 (1904).

3- Journ. A. Med. Assoc., July 16 (1904), p. 180.

PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

Plimmer1 made a very searching investigation of seventeen
cases of carefully diagnosed cancer in the Lister Institute of
Medicine. Not for any case examined did he secure favorable
results. "The radium had apparently no effect with regard
either to cure or relief of pain." Several of the patients having
died, careful microscopic examinations were made of sections
of cancerous tissue. In all the cases examined no changes were
found, either in the cancerous tissue or fibrous cell, and none
were degenerated. According to him it appears as if the emana-
. tions from radium can only act upon young and growing cells,
and the altered cells, especially if surrounded by old tissues, are
less and less affected. If there is a succession of fibrous tisue,
the cells are not at all affected. It is not clear that he used
the most modern containers for the radium.

The etiology of cancer is not yet understood. It appears
from the sifted evidence that thus far radium offers little
hope as a permanent cure for the dreaded disease, especially
after it has become deep-seated. It is generally accepted
as a fact, however, that temporary relief from pain and a retard-
ation of a cancerous growth may result from its application.
Its portability, easy dosage, remarkably localized action, render
radium a permanently valuable addition to the therapeutic arse-
nal, for the technique is simple.

The procedure of Williams,2 for guidance of others, is here-
with given : "When not in use the radio-active preparation
should be kept in a. thick lead box or envelope. When in use,
preferably, all sides except that side next to the diseased tissue,
should likewise be covered with thick lead to protect the oper-
ator. The compound should not be brought near photographic
plates, unless it, or the plates, be within lead, as it would injure
them."

"Method. The method of using the radiations from ra-
dium is simple. If the strongest action from the radium is
desired, the metal box containing the salts is placed on the part
to be treated ; in this case the box should first be covered with a
thin rubber cot, or other suitable substance, which can be readily

1. The Lancet, Apr. 16 (1904).

2. The Medical News, N. Y., Feb. 6 (1904).

AND THEIR THERAPEUTIC APPU CATIONS. 131

removed so that a new cot may be used for each patient and the
old one burned up. By this means, the radium capsule does not
come in direct contact with the part to be treated, but is separ-
ated from it by this new and clean covering. If a weaker action
of the radium salts is indicated, the capsule should be placed at a
greater or less distance, according to the needs of the case, the
intensity of the rays diminishing as the square of the distance.

"Exposure. It is important to remember that an over
exposure of a part may result in a burn, and that this burn may
not become evident in several days after the exposure has been
made. Further, that the exposures differ for different diseases,
even superficial ones. Experience, therefore, is necssary to
judge not only of the proper length of exposure, but also of its
frequency.

"Length and Frequency of Exposures. Exposures must in
some cases be longer, in others shorter, and the frequency with
which they are given must vary. In some cases the treatment
should be pushed ; in others harm, rather than good, would
result from this procedure. The exposure, then, must be
adapted to the special case, and further experience is necessary
to decide the best for all cases, but as a general rule, it may be
said that when the beta and gamma rays of pure radium bro-
mide (I have discarded the use of the weaker salts) are used
together, for the treatment of superficial lesions, and the radium
capsule is placed on the part to be treated, the length of the
exposure should be ten minutes to one hour, according to what
the practitioner desires to accomplish.

"Exposures should not be made every day. Two or three
times a week seems to me the safer procedure, as by this method
an interval is given during which progress can be watched.

"An exposure of many hours would be necessary if weaker
forms of radium are used, that is radium of 1000 to 8000 activ-
ity, before any special results could be obtained, and these
weaker forms would not be so efficient as compared with the
pure radium. Pure radium bromide is none too strong for the
work to be accomplished in certain cases ; in those in which the
full strength is not necessary, the radium, capsule can be placed
at any distance desired and the exposure can, also, be short-
ened."

In X-ray treatment dermatologists are agreed that great
care must be exercised as to idiosyncrasy of the patient, kind
of tube, vacuum, strength of the current, length of application,

I32T.HE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

frequency, etc. (See Chapter VII.) It has been asserted that
radium compounds of a definite strength may be used to obviate
many of these unknown factors. Piffard1 sounds a timely warn-
ing and most reasonably calls attention to the differences which
exist between the actual radio-activity of naked radium and effi-
cient radio-activity of a protected compound. "Radium affects
the photographic film and also the electroscope and electro-
meter, but it is by no means certain that the radiations that are
most active photographically are the ones that most strongly
ionize the air in the electrical apparatus, and it is still less cer-
tain as to which is the most efficient in its action on the human
tissues."

Fig. 60

Exact representations of a giant-cell sarcoma of the jaw of rapid
growth during two months. On the left the sketch is before treatment.
The teeth of the lad were so loose as to be readily removed by a string.
On the right may be seen the improvement after six months' treatment.
The tumor was punctured with a knife and a tube containing radium
bromide inserted for three hours at each treatment. Ossification set
in, the teeth became firm. Remnants of the giant-cells were found, how-
ever, by a pathological examination of the improved portion. The case
remains cured at one year from beginning treatment. (Robert Abbe,
Medical Record, 66, 321, 1904.)

Danycz2 demonstrated that the effect is more* intense in
young than adult animals. He applies this fact to explain the
selective action of the rays on neoplasms, while they traverse
skin and muscle without appreciable action on them.

1. Henry G. Piffard, Medical Record, June 18 (1904).

2. Action du Radium sur les differents tissues, Danycz. Semaine
Medicale, Paris, 24, No. i (1904).

AND THEIR THERAPEUTIC APPLICATIONS.

133

Fig. 6 1. -Apparatus of L,ieber for application of radium compounds
in medicine. The tubes are of aluminum. (Through courtesy of Hugo
Ivieber.)

The envelope of thin aluminum, for reasons already noted
according to Lieber, gives greater efficiency than one of glass,
mica or quartz. Morton suggests cellulose containers.

• It is assumed, of course, that any physician inaugurating
experiments on human subjects will have determined the
strength of the preparation before applying it. Even with that
knowledge, little is known to-day of the dosage. As adverted
to, the pathogenic action, i. e. the destructive effect, evidences
itself in temporary hyperaemia or extensive necrosis accom-
panying a long enduring ulcer. The difficulty in judging this
is due to the fact that oftentimes weeks intervene before ulcera-
tion becomes apparent. Robert Abbe1 learned that, as a result
of plunging a tube into a mammary tumor, the inactive encap-
sulation of radium when put into healthy muscular tissue and
peritoneum of animals, is no criterion for its action on morbid
tissue when buried within the tissues. Upon superficial healthy
tissue, radium compounds bring about necrosis by over excita-
tion; upon morbid cells they induce retrograde changes and a
substitutive fibro-hyperplasia.

Williams says that under no circumstances should the /?-
and y rays be used together for deep-seated diseases, because

i. Loc. cit.

I34-THE PHYSIOLOGICAL ACTION OF RADIO- ACTIVE SUBSTANCES

the /3-rays would cause serious injury before the y-rays had
time to produce a beneficial effect.

Einhonn compared the penetrating action of similar prep-
arations of radium with glass, hard rubber, celluloid, alumi-
num and ivory. Photographic effects indicated that the first
three allowed the penetration of the rays better than the last
two. He, also, suggested the use of radium in the transillu-
mination of various organs of the body. A capsule of radium
was held between the tongue and teeth. The cheekbones
became transilluminated. The suggestion was made that the
method might perhaps have a diagnostic use in the diseases of
the antrum. By the use of his "radio-diaphane" the radium
can be carried into the oesophagus, stomach, or rectum. The
method of procedure is as follows :

"The patient is examined with an empty stomach ; growths
from the thorax and abdomen being removed, the radio-dia-
phane is slightly moistened and introduced into the stomach. A
fluoroscope, with barium platino-cyanide screen, is used in. ob-
serving the rays. All observations must be noted in the dark
and after the eyes have become accustomed to the darkness.
The apparatus served satisfactorily in determining the position
of the large curvature of the stomach ; the descending colon or
sigmoid flexure, also, may be transilluminated by means of
radium, if the radio-diaphane, (Fig. 62), in the bowel is shorter
and of stiffer rubber. The bowels should be thoroughly flushed
with one or two quarts of water previous to the examination.
The instrument is introduced as far as possible without kinking,
the patient being placed on his back. The lower abdominal
region is inspected by means of a fluorescent screen. It usually
requires the inspiration of air to become visible ; deep inspiration
seems to lessen, while low inspiration increases the luminosity.""
In transilluminating the lungs from the esophagus, he learned
that it was possible to examine them anteriorly and posteriorly.

"Normally, moonshine appears where the lungs are ; a faint
shadow corresponding to the heart, is observed on the left side.
Doubtless marked inflation of the lungs would cause a change in
the transilluminancy."

:. Medical Record, July, 1904, p. 164.

AND THEIR THERAPEUTIC APPLICATIONS.

135

Fig. 62. — The Radiodiaphane.

By the transillumination of the stomach it appears possible
to discover tumors, as Einhorn reports he observed in one case.
He has, also, treated esophageal cancers in this way with
radium. In one case he was able to enlarge a stricture of the
esophagus. At first only the smallest size bougie could be
passed as far as the lower third ; after a month's treatment,
however, it improved so that a No. 30 bougie was passed into
the stomach and there was no difficulty in swallowing food.
From the few cases observed it appeared that partial shrinkage
of tumor causes the stricture to be reduced. There were no
disagreeable occurrences incidental to the treatment. There
was a diminution of pain in some cases, but not in all. No
complete cure is reported, but decided improvements were
observed.

Exner1 reported three cases of dilatation of stricture by
similar treatment with radium. The stricture resulted from
esophageal cancer.

As a further illustration of the variety of evidence and its
frequent contradictory character, attention is directed to the
statement of Metzenbaum,2 who says: "From very careful
observations no difference could be noticed in the physical or
therapeutic results when using radium of 100 activity or 7000
activity."

1. Wiener klinische Wochenschrift, IV (1904)-

2. Louisville Journal of Medicine and Surgery, 188 (1904).

E PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

Darier1 is reported as having used radium successfully as
an analgesic and as a curative agent in nervous spasms and
paralysis.

Touching the action of X-rays on bacteria, Bear2 experi-
mented with bacillus coli communus, bacillus typhosus, staphy-
lococcus, streptococcus, Klebs-Loefler bacillus, etc., using an
exposure of one hour at a distance of ten inches, and found no
effect, whatever the make of the tube or the method of excite-
ment.

Aschkinass3 and Caspari4 first showed that the rays of
radium interfere with the development of bacteria. PfeifTer
and Friedberger proved its bactericidal action on saprophytic
as well as pathogenic microbes. Dixon and Wigham,5 con-
tinuing their experiments on the action of radium bromide on
plants, found in the case of certain bacilli, for example B-pyo-
cyaneus, typhosus, prodigiosus, and anthracis in an agar culture
medium, that the /3- radiation exercises a marked inhibitory
action on their growth. A four-day exposure at a distance of
4.5 c. m. of 5 m. g. of radium bromide does not appear suffi-
cient to kill the bacteria, but arrests their growth, and main-
tains a patch on an agar plate, inoculated with any of these
organisms, sterile. A broth tube, however, inoculated with
these in most cases developed the organisms, showing that
while the growth was inhibited in the patch, all the organisms
were not killed.

Henry Crookese has shown that various bacterial cultures
after exposure to the action of 10 mgms. of radium bromide,

1. Consular Report, Guenther, Frankfort, Germany, Mch. u (1904).

2. "Effect of Rontgen rays on Certain Bacteria," Journ. Advanced
Therapeutics of New York, June (1903).

3- Arch. f. d. ges. Physiol. (Bonn), 86, 603.

4. Allg. Med. Centr. Ztg. (Berlin), 72, 590 (1903).

5. "Action of Radium on Bacteria," Nature.

6. "Bactericidal Properties of the Emanations of Radium," Chem.
News, 87, 308.

AND THEIR THERAPEUTIC APPLICATIONS. 137

about 3 cms. distant, were killed. When the plates were incu-
bated for 24 to 48 hours, it was noted that the immediate por-
tion of the plate which had been subjected to the action of the
rays showed a bare space free from bacterial growth.

Experiments in our laboratory (University of North Caro-
lina) by Manning, with radium chloride of 7000 activity, indi-
cated an actual stimulation of their growth.

Green1 found that when bacterial cultures were subjected
to the action of radium bromide and then removed, they pos-
sessed sufficient activity to affect the photographic plate, even
through a double layer of lead foil.

Van Buren and Zinsser2 report the result of the effect of
radium of 300,000 activity upon bacteria. They exposed the
bacillus typhus, staphylohemia, pyrogensis aureus from 8 to 19
hours in the dark without any effect. They say this may have
been due to the fact that the radium' was confined within glass
or on account of the shortness of exposure, but they assert that
their observations give small promise of achieving brilliant
therapeutic results with it as a bactericide, as prophesied by
others.

Prescott3 arrived at the following conclusions :

Radium rays have no effect upon fresh cultures of B-coli,
B-diphtheriae, or saccharomyces cerevisiae at a distance of one
centimeter when the time of exposure is less than ninety min-
utes.

Any advantages derived from the therapeutic use of
radium must be explained in some other way than by the direct
weakening or destruction of the micro-organisms of disease.

The use of radium tubes in the treatment of diphtheria
cannot be recommended or regarded as a substitute for anti-
toxin.

Ackroyd4 studied the action of radium on milk, and
Schmidt-Nielson reported that the action of radium in the

1. Nature 70, 69.

2. American Medicine, Dec. 26, 1903.

3. Science, N. S., 20, 247.

4. Nature 70, 55 (1904).

I38THE PHYSIOLOGICAL ACTION OF RADIO-ACTIVE SUBSTANCES

curdling of milk is minimal. Any action it showed upon the
chymosin was attributed not to the Becquerel rays, but to the
phosphorescence of the generated ultra-violet rays.

Dr. Margaret Mary Sharpe, of London, appears to have
been the first to use radiant matter in the removal of hair as a
professional procedure.

From what we have learned there appears to be little in
the suggestion that radio-activity may supplant chemicals used
for the preservation of food.

r—^rmW-f

• •>' v<r

Fig. 63

This shows the hindering effect a radium compound has upon the
germination of seed. (Through the courtesy of Dr. Robert Abbe.)

It has even been suggested that radium will solve the prob-
lem .of determining the sex of children before birth.

Many other suggestions have resulted from the unchecked
play of imagination ; for example, the prevention of mal de mzr
by the use of radium.

Soddy is reported as having suggested the inhalation of
thorium emanations for tuberculosis. Tracy, by a photographic
method, reports the radio-activity of the breath after such
inhalations.

Soddy has noted that if a radium salt be dissolved in
water the emanations are immediately evolved, and collect in

AND THEIR THERAPEUTIC APPLICATIONS.

139

the air above the solution. If the emanations be swept at once
into the lungs they serve as a germicidal agent in tuberculosis.
Lieber asserts its value in the case of hoarseness with himself.

Morton states he saturated distilled water with radium
emanations and this was administered to the patient. It
appeared to create fluorescence in the medicines that may have
been previously administered. Apparently the rays thrown off
from the fluorescing substance become healing agents. This
mode of treatment has also been used by Paul-Edward, Radio-
grapher of the General Hospital, London.

Blood has been removed from persons who have acquired
radio-activity. It affects photographic plates through translu-
cent substances. This is a case, apparently, of induced activity.

The method, according to Morton, of saturating the water
is shown in the accompanying figure. (Fig. 63.)

Fig. 63

Morton's method for saturating water with the emanations of
radium. The radium compound is in the open vessel in flask 2. Gas
is forced by the compressor, 3, over the radium, to sweep the emana-
tions through the water in i.

Saake1 refers to the radio-active substances of the air
reported by Elster and Geitel as being from 3 to 5 times as
great in the mountains as at the level of the sea. ''The differ-
ence in the tension between the positive air and the negative

i. "Ein. bisher unbekannter Faktor des Hohenklimas," Munchener
Med. Wochenschrift 51, i (1904).

PHYSIOLOGICAL ACTION OF RADIO- ACTIVE SUBSTANCES

earth — the potential — also increases with the altitude. Experi-
ments indicate that these electric and radio-active factors have
some share in the benefits of the mountain climate and they
might be artificially increased." The writer repeats such state-
ments with trepidation, for all have been either misunderstood
or unwarranted conclusions drawn by the zealous newsgather-
ers with unfortunate consequent delusions on the part of the
ill. One instance is reported1 where at least "one shrewd specu-
lator in human misery proposes soon to start a sort of radium
consumption farm, where he will advertise to do wonders for
affected lungs by means of radio-active air — and handsome
fees."

Frequent suggestions have been made to prepare salves,
ointments, etc., with chemically inert preparations of radio-
active substances.

Morton2 has inaugurated a novel method of treatment by
which the introduction of light within the human tissues them-
selves is claimed. The X-ray and radium compounds are used
merely as exciters of the fluorescent substances already within
fluids of the human body or by injected fluorescing substances.
He says,3 "I now regard the X-ray and radium as exciters of
light, and I think that the curative effects are due to the fluores-
cent qualities of the fluids of the human body, particularly when
these fluids have -been made more fluorescent, that is to say,
artificially fluorescent by the use of various fluorescent solu-
tions."

Metzenbaum, however, says: "The conclusions drawn
from nearly one hundred experiments give positive proof that
while suspending tubes of radium of various strength for long
periods in various solutions and various powders, that neither
these solutions nor the powders are capable of affecting photo-
graphic plates, and are therefore not rendered radio-active, and

I. "The Sense and Nonsense about Radium," Cleveland Moffett,
Success, April (1904).

2.. New York Medical Journal, Feb. 13 and 20 (1904).
3. Personal letter to the writer.

AND THEIR THERAPEUTIC APPLICATIONS. 141

therefore neither the solution nor the powders can in any way
affect the metabolism or pathology of living organisms."

In view of the most recent work of Ramsay (Chapter V),
it does not seem improbable that substances may become radio-
active without actual contact with the emanations.

It is too soon to draw any conclusions from much that has
been done. It is unwise to make any final statements. How-
ever, we know this much : that the radium rays possess the
power of dilating the vessels ; that they have an electric action ;
also, an influence upon the cells of quickly growing tissues and
possibly bactericidal properties. These three factors give bright
promise of its therapeutic use, when we shall have learned more
about this wonderful substance.

142 OTHER THERAPEUTIC RADIATIONS.

CHAPTER VII.

OTHER THERAPEUTIC RADIATIONS.
The Rontgen Rays.

Attention has already been directed to the fact that when
a Crookes tube is placed in series with the poles of a static
machine, or the secondary terminals of an induction coil, it
becomes the seat of three classes of radiations: (a) the anode
rays, or kanalstrahlen of Goldstein; (b) the cathode rays;
and (c) the X-rays of Rontgen.

The Goldstein rays are confined to the interior of the
tube and hence, from the standpoint of the physician, are neg-
ligible. The cathode rays are much more penetrating and in
part, according to Oliver Lodge,1 traverse the tube and possibly
may be the chief factor in producing the cutaneous reaction
that is observed when the Crookes tube is employed for thera-
peutic purposes. The X-rays are without the tubes. These
are vastly more penetrating than the others. This penetrating
power varies inversely with the density of the substance on
which they impinge. Substances opaque to light, as aluminum,
are readily penetrated, while many substances transparent to
light, as rock salt, are remarkably opaque to the X-rays.

It was known for some time that the Rontgen rays, in
addition to their value as an aid to surgical diagnosis, possessed
peculiar properties which gave promise in the treatment of
certain forms of disease, especially those affecting the skin.2

1. Archives of the Rontgen Rays, April (1904).

2. "Lupus," Pusey, Journ. Am. Med. Ass'n., 35, 1476 (1900). The
method of Schiff and Freund, of Vienna, was used. In calling atten-
tion to the work of Kummel, Pusey states that certainly none of the
usual methods of treatment by surgical means could produce such a
result.

OTHER TPIERAPEUTIC RADIATIONS.

'43

For a clearer conception of this phase of our subject it
becomes necessary to call attention, incidentally, to some of the
most recent work in the application of the "X-light" to the
treatment of disease. The reader interested in such may secure
first hand knowledge of this form of medical practice by refer-
ring to fuller and authoritative works.1

The illustration shows a case before and after treatment with X-
rays. A. D.. twelve years of age. Microscopical diagnosis, lympho-
sarcoma after first operation and round-celled sarcoma after second
operation. Duration, seven years. (Williams, Medical News, Feb. 6,
1904.)

Pusey2 reports the favorable treatment of sarcoma by
X-rays, and says that in certain cases, which cannot for any
reason be treated successfully by surgical means, the effect of
X-rays should be tried. And further, that in cases of sarcoma

i. As for example, F. H. Williams's, "The Technique of X-ray
Therapy as Applied to Diseases of the Skin," and L. E. Schmidt, Journ.
Am. Med. Assn., 40, n, 1903. Also Rollins.

2.. Journ. Am. Med. Assn., 38, 166.

144 OTHER THERAPEUTIC RADIATIONS.

which have been treated surgically, the subsequent use of
X-ray exposures as a prophylactic, is a procedure which should
be considered.

Bartholmy1 reports a number of cases of cutaneous lesions
produced by the application of the X-rays. He urges caution,
and states that it is still premature to introduce the radio-
therapy in a current practice, one case of burn being observed
five minutes after the first application. The physician should
not be held responsible for this, any more than for death during
chloroform narcosis, when all the rules of science have been
complied with. In spite of precautions, accidents are liable
to happen when least anticipated.

Rurio-Jicinsky2 lays down general rules for treatment with
X-rays, concerning the kind of tube to be used in protection of
the hair, eyes, etc., while Ross and Wilbert3 found the anaes-
thetic effect of the X-ray a decided advantage, though they
did not find it was valuable as a curative agent in all malig-
nant growths.

Leonard4 in writing of the Rontgen treatment of malig-
nant diseases, states that the alterative and destructive action
produce retrograde changes. In large subcutaneous growths
of low vitality, such a rapid destruction may take place as to
flood the system with toxins and cause a fatal auto-intoxica-
tion and septicemia." The bad effects noted by some observers,
such as the stimulation of the growth of tumors, were probably
due to this cause, or to under stimulation by too small a dosage.
Operative treatment should precede and the X-ray treatment
deal with the residue that has escaped the knife. "It must be
employed with as great care as any other agent possessing
such marked alterative properties."

i. Annales de Dermatologie, Paris, February, 1901.

2.. N. Y. Med. Journ.. Nov. 15, 1902.

3. Therapeutic Gazette, Detroit, Feb. 15, 1903.

4. Phila. Med. Journ., Feb. 14 (1903).

OTHER THERAPEUTIC RADIATIONS. 145

Walker i reports the cure of a case of alveolar melanotic
sarcoma.

Coley,2 summarizing the X-ray treatment of malignant
tumors, states that they have an inhibitory action on all forms
of malignant tumors ; yet the number of cases is insufficient
to enable us to state what particular varieties are most suscep-
tible to these influences.

Pfahler;' in his comments on X-ray treatment of cancer
says : "To-day the medical profession seems to recognize it
as a valuable therapeutic agent in certain forms of cancer.'*
Among other conclusions drawn, he states that the time re-
quired to cure superficial cancer is usually from two to six:
months. "We can recommend the use of X-ray in all carci-
nomata, but especially in those that are inoperable or in which
operation is refused."

Again this same author* gives a number oJf conclusions
drawn from treatment of carcinoma and tuberculosis with
Rontgen rays. Among these it may be mentioned that the
X-rays are of undoubted value in the treatment of certain
cases of both superficial and deep-seated carcinoma and tuber-
culosis. Yet there are idiosyncrasies in certain persons which:
render them most susceptible to the X-rays. In these people
deeper burns may occur, in spite of the most careful treatment.
Epithelioma involving the mucous membrane is much less likely
to be involved in these effects than that which involves the
skin. There is not likely to be any interference with the sense
of sight, even if the X-rays are used directly over the eye.
Tuberculosis, whether 'of the skin or of the glands, yields in
certain cases to the X-rays. Epithelioma of the mucous mem-
brane should be removed as soon as possible by the knife and
that followed by the X-ray treatment. Operable cases should
be operated on and that followed by the X-ray treatment.

1. Journ. Am. Med. Assn., 40, 1214 (1903).

2. Med. Record, New York, March 21 (1903).

3. Journ. Am. Med. Assn., 40. 8.

4- Journ. Am. Med. Assn., 41, 1406 (1903).

146 OTHER THERAPEUTIC RADIATIONS.

The X-ray is "not only a very valuable therapeutic agent
but also a very dangerous one," for as Zeisler1 has said, ''Who-
ever is making extensive use of the Rontgen rays is bound to
have, sooner or later, some unpleasant experience with the much
dreaded X-ray burns."

The following diseases have been treated by the X-rays
with variable success :

Lupus vulgaris and erythematosus, scrofuloderma, hyper-
trichosis, acne, sycosis, epithelioma, psoriasis (not permanent),
lichenplanus, keratosis palmaris, eczema and pruritus, clavus,
hyperidrosis nasi, and dermatitis staphylogenes.

Concerning X-rays and cancer, the editor of the Journal
of the American Medical Association says, "That the X-rays
have a powerful effect on tissue is undeniable. The evidence
seems strong, if not altogether conclusive, that they have a
selective action on certain morbid celled proliferations; that
they check malignant growth by their destructive action on
the surrounding healthy tissues is so much less that it can be
safely considered as negligible when the beneficial effects are
taken into account."

Ultra-Violet Rays.

The spectrum of the solar rays, as we analyze them at the
earth's surface, is found to consist of three distinct portions:

(1) At the lower- end certain invisible radiations of compara-
tively long wave-length, and commonly spoken of as the infra-
red portion of the spectrum. So far as we are aware there
has been no separate and distinct therapeutic application of
these rays, other than their employment as thermic agents.

(2) The luminous portion of the spectrum with its colored
gamut from red to violet, passing upward from B longer to
shorter wave lengths from Fraunhofer's lines A to H. (3)
The invisible portion of still shorter wave-lengths and indef-
inite extent, known as the ultra-violet.

Near the surface of the sun this region is undoubtedly
of very great length, but as the undulations pass through the

i. Journ. Am. Med. Assn., 40, 511 (1903).

OTHER THERAPEUTIC RADIATIONS. 147

atmosphere, the waves of shortest length are absorbed and
do not reach us. Fortunately these shorter undulations become
known to us through artificial sources and it is by this means
that physicians have been enabled to utilize the ultra-violet
rays in the treatment of disease.

The chief sources of the ultra-violet rays, available for
experimental purposes, are the electric arc and the radiations of
the spark of the high tension current of a transformer in con-
nection with a condenser.

The electric arc with carbon terminals emits a larger rela-
tive proportion of ultra-violet rays than we find in the solar-
radiations. If iron terminals be substituted for the carbon,
the proportion of ultra-violet is still greater; and if the con-
denser spark is made to pass between iron terminals, we will
have the richest source of ultra-violet rays now known to us.

The most convenient means for detecting the ultra-violet
rays are their effect on certain fluorescent minerals, notably
willemite and calcite and their ability to ionize gases, as
shown by their effect on a negatively charged electroscope.

Willemite associated with calcite and other minerals from
Franklin, N. J., and calcite associated with schefferite and
braunite from Sweden, serve admirably as aids to an approx-
imate valuation of the ultra-violet rays, as shown by Kunz and
the writer.

When subjected to the rays from the carbon-arc willemite
fluoresces green, but the calcite is unchanged; to the iron-arc
the green fluorescence is more brilliant and the calcite changes
from white to very faint pink ; when exposed to the rays from
the condenser-spark, between iron terminals, the green fluor-
escence of the willemite is extremely brilliant, the calcite is
changed to a bright pink, and in specimens from Sweden to
a brilliant red.

When an electroscope, charged negatively, is exposed to
the carbon-arc (Finsen-Reyn lamp) it is slowly discharged;
that is, in from five to ten minutes ; when exposed, at the same

148 OTHER THERAPEUTIC RADIATIONS.

distance, to the iron-arc, in from one and a half to two min-
utes; and when exposed to the condenser-spark, between iron
terminals, in less than half a minute. The discharge of the
electroscope in these instances is brought about by the ioniz-
ing influence of the ultra-violet rays on the air that lies be-
tween the parallel plates of the electroscope. The ionized air
thus becomes a conductor of electricity and this permits the
charge of the insulated gold-leaf to escape to earth.

The therapeutic utilization of the luminous as well as the
non-luminous portions of the spectrum have been thoroughly
and well discussed by others, especially on account of the bril-
liant work of the lamented Finsen.

The Piffard-Rays.

Recently there appeared a paper1 describing what may be
termed the Piffard-rays, after the physician who discovered
them and who is using them with success in his practice.

The lamp (Fig. 65) is furnished in front with a thin
quartz plate, which is transparent to ultra-violet rays, while
glass is opaque to them. If the face of the lamp, with the
quartz in situ, be applied to a piece of photographic paper
(Solio) and the lamp actuated by a suitable coil, a strong im-
pression will be made on the paper in about thirty seconds.
If the experiment is repeated with the quartz removed, the
result is substantially the same.

Ultra-violet rays, as is well known, will discharge an
electroscope if charged negatively but not if charged posi-
tively.

On trial Piffard found that the lamp with the quartz in
front discharged the negative electroscope in about 20 sec-
onds, but with the quartz removed discharged it instantly ; that
is, within less than one second. He also found further that
the radiations from the unobstructed spark would discharge
an electroscope charged positively.

It was clear from this that in addition to the ultra-violet
rays he was dealing with another class of radiations that only

i. The Medical News, 85, 1057 (1904).

OTHER THERAPEUTIC RADIATIONS. 149

Fig. 65. — Piffard's Ultra- Violet Lamp. The technique recommended
is as follows : If the appliance be used with a ceil, a single Leyden jar
should be employed, with inner armature connected with one of the
secondary terminals, and the outer armature with the other terminal of
the secondary of the coil. The lamp is then connected directly to the
secondary by its cords. Piffard prefers a Wehnelt interrupter adjusted to
give a current of five to six amperes through the primary of the coil.
The armatures should not exceed 40 square inches of foil in each. This
is for the three spark lamp. For the one spark "ionizer" a lesser amount
of energy is preferable. The first application should never exceed ten
minutes. If connected with a static machine use two Leyden jars,
the armatures cf which should each have a foil surface of at least 100
square inches. The outer armatures of the jars should be connected
together, and the lamp terminals connected to the pole pieces of the
static machine. The first application should not exceed 15 minutes
with the spark from 15 to 20 millimeters from the lesion.

slightly affected the photographic plate, but acted very ener-
getically on the electroscope.

In default of any means of determining the exact nature
of these radiations he assumed that they were negative elec-
trons and predicted that they would act very energetically on
the skin or any other tissue with which they came in contact;
that the character of the reaction would resemble that from the
X-rays and radium, except that it would make its appearance
more promptly.

If the radiations in question were negative electrons, as
apparently are the cathode rays of the Crookes tube, and the
beta rays of radium, they would of course be deflected by a
strong magnetic field, which Pegram and Milton Franklin
found was not the case.

150

OTHER THERAPEUTIC RADIATIONS.

V%---^.-— ( Jh WAITE &IBARTLETT M.F.G' CO. N.Y. ( 9i)

Fig. 66. — Piffard's Electroscope, later model.

E. Wiedemann1 described a new form of radiation to
which he gave the name of Entladungsstrahlcn, and stated
that it was not deflectible by the magnet and would not pass
through fluorspar which readily transmits the ultra-violet rays.
He does not appear to have examined the radiations with the
electroscope. It is quite possible therefore that Wiedemamrs
observations related to the Piffard rays.

In discussing the question of ions, J. J. Thomson says/
that if we have a spark one centimeter long in connection with a
condenser of 1000 c. m. capacity the pressure developed will
be equal to that of 660 atmospheres, (equal to about five tons
to the square inch). This pressure, however, diminishes with
the distance from the spark according to the law of inverse
squares.

When we consider the enormous velocity with which ions
are projected in consequence of the pressure behind them, and

1. Zeitschrift fur Electrochemie, July 20, 1895.

2. Conduction of Electricity through Gases. Cambridge, Eng., 1903,
p. 392.

OTHER THERAPEUTIC RADIATIONS. 151

the rapidity with which they are developed, it is quite within
reason to assume that they will be capable of exerting a con-
siderable influence on tissues that are brought within a centi-
meter or two of their point of origin. Piffard has found,
clinically, that his rays do exert a very powerful influence on
the skin; and that the reaction is similar in character to that
of the X-rays and of radium ; and that it appears much more
promptly. Like them also it may produce a curative or a

Fig. 67. — Piffard's Spark-ionizer.

152 OTHER THERAPEUTIC RADIATIONS.

destructive effect according to the intensity of the spark and
the duration of its application.

When the spark is produced between iron electrodes, with
one or more intervening gaps, the total length of the gaps
need not exceed one centimeter. If the lamp be used in con-
nection with a coil and suitable condenser, an application of
about five minutes with the sparks about 15 m. m. from the
tissue, a decided reaction will be obtained in soft morbid
epithelial and other degenerating tissue. A similar applica-
tion for 15 minutes has resulted in the sloughing out of a lupus
nodule. It is important, therefore, that care should be used
and especially at the beginning of treatment in any given case.
These condenser spark radiations have also been used suc-
cessfully by Robert Abbe, Milton Franklin, and Dieffenbach.

The use of X-rays in connection with uterine cancer and
some epitheliomatous conditions of the buccal cavity present
mechanical difficulties that it is sometimes inconvenient to
overcome. Piffard, to overcome such in the application of
his rays, designed what he calls a "spark-ionizer," which may
be introduced through a speculum or other suitable shield.
The name is given on account of utilization of both the ultra-
violet light and the ions ( ?).

While it is too new for unqualified statements the indica-
tions certainly are promising.

153

INDEX.

Abbe 116, 122, 126, 133, 152

Absorption, power of different

rays (Beequerel) 16

Ackroyd 44, 137

Acne 12f

Actinium 5

Actinium At. Wt 58

Actinium— emanation 1)1

Actinium— from pitchblende 56

Actinium— methods of separation 56
Actinium— oxide and radium bro-
mide -r>7

Action of radio-active Th 49

Action radium bromide and ac-
tinium oxide 57

Adamkiewicz serum 126

Adams 65

Aeschynite 20

Af anas jew 21

Alexander 108

Allan 65

a and/2 bromo-allo-cinnamic acids. 44
a and j3 particles — comparison. .114

a and ft particles — Laws of 110

a emanations— order of penetra-
tion 41

a rays, properties of 15, 40

Alveolar melanotic sarcoma 145

Aluminum tube for radium (Lie-

ber) 125

Amber— photographic action of

Beequerel rays through 13

Anode 1

Anode rays 142

Antitoxin 137

Autunite 13, 20, 21

Apolant -. 127

Apparatus for applying radium

compounds 123

Apparatus for application radium

compounds 133

Apparatus for condensing the
emanations . . . 80

Apparatus for examination active

body — Curie 17

Apparatus for illustrating the dif-
fusions and condensation of

emanations 71

Apparatus for demonstrating em-
anation of radium is a gas 70

Apparatus for determination of

electrical conductivity 35

Apparatus of Dewar and Curie. . . 31
Apparatus for showing ratio of ra-
dium and uranium 99

Apparatus used by Mine. Curie
for measuring the intensity of

radiation 18

Application of radium preparation
in local treatment— Morton. .. .122

Armstrong and Lowry 103

Arnold 9

Arsonval 9

Aschkinass 136

Atomic Degradation 103

At. Wt. constituent Ceylon Min-
eral 53

Atoms — electrically charged 97

Austrian Government 24

Bacilli 136, 137

Bacterial Cultures 136

Bacterial growth 137

Barium — similarity of radium to. . 28

Barium— artificial active 64

Barium Bromide, radio-activity of 27
Barium platino-cyanide screen... 6
Barium Sulphate emanation— X .. 87

Barker 50

Barnes— Heat emission, etc., ra-
dium emanation 81, 89

Bartholmy 144

Baskerville 9

Baskerville — Inactive thorium. . .107
Baskerville — Radio-active thorium

from monazite 52

Baskerville — Thorium constituents 98

154

INDEX.

Baskerville and Kunz— Tiffnnyite

diamond 84

Baskerville and Kunz— Thuringian

glass, etc 74

Baskerville and Lemly— separa-
tion thorium, etc 51

Baskerville and Lichteuthaeler. . . 63
Baskerville and Lockhart— Effect
on diamonds from condensed

emanations 74

Baskerville and Lockhart— rare-
earth minerals 77

Baskerville and Lockhart— theory

of 101

Baskerville and Zerhan— Thorium

from South American Mineral.. 52
Baskerville and Zerban— Th. from

South American Mineral 99

Batelli and Maccarone 90

Bear 136

Beattie 11

Becquerel— activity uranium not

constant 94

Becquerel— a particles 40

Becquerel-a rays 15

Becquerel— black light 9

Becquerel— Conversion yellow P.

to red 43

Becquerel— energy from uranium. 16
Becquerel— examination of polo-
nium 54

Becquerel— X-Rays 41

Becquerel— invisible radiations of

uranium 46

Becquerel— radium sore 115

Becquerel— secondary radio-activ-
ity of metals 85

Becquerel— speed corpuscles from

radio-active substances 106

Becquerel— uranium 47

Becquerel Rays 13. 18

Becquerel rays — effect on nerve

cells 129

Becquerel and Curie .116

Beilly 83

Bemont 22

Benoist 42

Berndt 53

Berthelot 36, 44

ft Rays — properties of 14

ft or Cathode rays 38

Bismuth, platinum and palladium 55
Bismuth— property of emitting

rays 55

Bismuth and radio-tellurium.. .. 61

Black 19, 43

"Black Light" 9

Blandamur 119

Blende, Sidot's 9

Blood 139

Bohemian pitchblende 48

Bohm 120

Boltwood— apparatus for showing
riatio of radium and uranium.. 99

Boltwood 23, 24, 25, 103

Borgman 66

Bougie 135

Broggerite 13

Broggerite, extraction two ele-
ments ( ?) from 59

Broggerite— two elements from

and at. wts 59

Brooks 79, 87

Buckwalter 14, 15

Bulkley 129

Bumstead and Wheeler 65

Bun sen Colorimeter 31

Burton . ..65, 67

Calcite and Willemite 147

Calcium sulphide, phosphorescent 9
Cameo, photographic of Becquerel

rays through 13

Cancer 127, 145, 146, 152

Cancer, epithelial 126

Cancer — etiology 130

Cancerous tissue 130

Carcinoma 128

Carcinoma of the oesophagus. .. .121

Carnotite 14, 20

Carnotite— extraction of radium

from 25

Carnotite impression 14

Carolinium 53

Caspar! 136

Catalytic agent 97

Catalysis — radio-activity a form of 97

Cathode % 1

Cathode rays 2, 6, 142

Celluloid, etc.— loss of activity . . 91

Cervix uteri 124

Cerebo-Spinal flexures 128

Ceylon Mineral 52

Chalcolite 20

Chalcolite— artificial, radio-activity

of 21

Chemical action radium com-
pounds 43

Chymosia 138

INDKX.

Clark Cell 44

Cleaves 123

Cleveite 13, 20

Clock— Strutt's Radium 10.~>

Coley 145

Coley serum 120

Coli communus bacillus 136

Collier 13

Condensation of radium emana-
tion 81

Corneal Opacity 118

Conductivity of the Air 34

Cook 66

Coppel 35

Coral, luminescence of — under the

action of cathode rays 3

Cornwallis 20

Corpuscles 4, 5

Crookes, Henry— bacterial cul-
tures 136

Crookes and Dewar 73, 88

Crookes and Thomson 101

Crookes— a rays 40

Crookes — deviable rays and ca-
thode 94

Crookes— Elster and Geitel 55

Crookes — examination uranium

minerals, etc 11

Crookes— Investigation of phe

nomena in high vacua 2

Crookes— photographic method ... 52

Crookes— polonium 53

Crookes — radiant mater of radium 70
Crookes — radio-active elements
and abstraction energy from a

gas 100

Crookes's Railway Tube 4

Crookes's Rays 103

Crookes's Spinthariscope 73

Crookes — study spark spectrum,

radium 28

Crookes Tube 2, 7, 142

Crookes tube provided with a

window 3

Crookes— uranium 36

Crookes — uranium nitrate 47, 48

Cryellitzer 117

Curie and Debierne 73, 77, 90

Curie and Danne 76, 70

Curie and Dewar 83

Curie and Giesel 30

Curie, Mme. S. a- rays polo-
nium 40

Curie and Laborde 30, 31, 06. 100

Curie and Rutherford.. ...93

Curie, Mnie. S.— apparatus for
measuring intensity of radiation 18

Curie, Mme. S.— artificial chalco-
hite 25

Curie, Mme. S.— at. wt. radium... 29

Curie, Mme. S.— bismuth and po-
lonium 55

Curie, Mine. S.— calcium sulphide 0

Curie, Mme. S.— estimate of radi-
um emission 106

Curie, Mme. S.— exam, uranium
salts 16

Curie, Mme. S.— excited radio-
activity 85

Curie, Mme. S. — exposure of sub-
stances to radium 87

Curie and Becquerel — exposure of
arm to radium 115

Curie, Mme. S.— general theory
radio-activity 100

Curie, Mme. S.— Law for dissipa-
tion of excited radio-activity... 01

Curie, Mme. S.— Polonium 53, 54

Curie, Mme. S.— Polonium of 60

Curie, Mme. S. — Preparation of
artificial chalcolite 21

Curie, Mme. S. — "radio-activity"
of uranium and compounds 10

Curie, Mine. S.— radio-activity of
uranium 51

Curie, Mine. S.— radium and Roent-
gen rays 107

Curie, Mme. S.— Radio-activity an
atomic phenomenon 04

Curie, Mine. S.— Radio-activity
uranium, thorium, radium, ac-
tinium 55

Curie, Mme. S.— radium emana-
tions 33

Curie, Mme. S.— Radium, power
of absorbing rays (?) 107

Curie, Mme. S.— Table intensity
of current with metallic ura-
nium 20

Curie, Mme. S.— Thorium, radio-
activity of 48

Curie, Mme. S.— Uranium, thor-
ium, radium and actinium ac-
tivity 55

Curie, P.— character of radium
rays 38

Curie, P.— conductivity of air un-
der influence of radium 34

Curie. P.— excited radio-activity. 85

156

INDEX.

Curie, P.— exposure of substances
to radium 87

Curie, P.— General theory radio-
activity 100

Curie, P.— Preparation of radium. 27

Curie, P.— Radio-activity uranium,
thorium, radium, actinium 55

Curie, P.— radium emanations. ... 33

Curie, P.— Radium, power of ab-
sorbing R. Rays (?) 107

Curie, P.— rate of decay of activ-
ity, radium bromide 71, 72

Curie, P.— Theory of radio-activ-
ity 100

Current of saturation, limiting
current 18

Cyclitis and irido 128

Danlos— and lupus patient 119

Danne, M. Jacques— Extraction of
radium from pitchblende and

carnotite 26

Danne 76

Danne — Emanation radium 79

Danycz 119, 132

Dauycz and Bohm 120

Darier 128, 136

Darwin 106

Davis 92, 103

D'Arsonval 9

Debierne, activity actinium 58

Debierne— Artificial active barium 64

Debierue— excited activity 77

Debierne— excited radio-activity.. 90
Debierne— Factory process; new
element assximption, radium... 25

Debierne — gas in vacuum 73

Debierne — Radium in vacuum.... 71

Debierne 90, 91

Decay of activity 10!)

De Hemptinne 98

Demarcay 53

Demarcay, radium examination.. I'-")

Demarcay, radium spectrum 28

Descoundres— a rays of polonium. 41

Descoundres 40

Desconndres — helium spectrum ... 84

DeSmolan 11

Detection of radio-activity (Bolt-
wood) 24

Dewar — nitrogen 83

Dewar — scintillations 73

Diamonds, luminescence of, under
the action of cathode rays 3

r>:;

Diamond, photographic action of

Becquerel rays through 13

Dieff enbach I52

Diphtheria 13>7

Diseases— deep seated 133

Disintegration of radium atom.

Dolezalek

Dorn 7()

Dorn and Forch $'

Du Pont ' °'

Dutch Metal 41

Eczema

Effect of radium bromide on
photo plate

Einhorn 1:i4

Electric charge of cathode rays. . •>

Electric discharge

Electric discharge in vacuo

Electrical conductivity 35

Electric field, action of, upon

cathode rays

Electric spark

Electrometer 1~

"Electronides" 102

Electrons H2

Electroscope 7, 8, 9, 41

Electroscope, action of X rays

upon the '

Electroscope. Mine. Curie's. .. .17, 19

Electroscope, Rutherford's 2i

Electroscope, Piffard's 150

Elements— No. of Radio-active 64

Elster and Geitel,

11, 16, 38, 66, 68. 139

Emanation— absorption of 76

Emanation— at. wt. 200 81

Emanation— amt. stored in non-
emanating radium 76

Emanation— changes in 114

Emanation— chemical nature 78

Emanation— condensation of 79

Emanation — decay activity 109

Emanation— heating effect of 89

Emanation— influence radium on

bodies 78

Emanation— luminosity of 79

Emanation— power of producing

persists in the atom

Emanation— radiation of 81

Emanation of radium gas 70

Emanation — rate of decay of 75

Emanation— Thorium vs. radium. 81

INDEX.

Emanation— wt. of HI

Emanation — X 86

Emanation— X. of thorium 87

Emaniiun 62

Energy, produce,! by cathode rays 4

Energy of Becquerel rays 16

Entladuugstrahleu 150

Epidermis 115

Epithelial cancer —treatment of. .126
Epithelioma — mucous membrane. .145

E-rays 90

Epithelioma 120, 129

Excited activity 95

Excited radio-activity 85

Exposure — length and frequency. .131

Exner 28, 121, 135

Exner— Polonium 53

Eye . ..116, 117

Facial paralysis 128 |

Fehrle 90

Fergusonite 20

Finsen-Reyn lamp 147

Foveau de Courmelles 128

Fluorescence of glass 10

Fluorescence of glass in Crookes

tube 2

Fluorescing substances 10

Flourspar, photographic action of

Becquerel rays through 13

Forch 92

Franklin 5, 104, 149, 152

Friedberger . .136

Gadaud ......................... 119

y rays .......................... 41

Gassiott ........................ 1

Gates .......................... 86

Gteissler tube ............. 1, 2, 3, 84

Gegner prize .................... 22

Giant-cell sarcoma (Abbe) ....... 132

Glaucoma ...................... 118

Globulin, coagulation of ........ 45

Goldberg ........................ 123

Goldstein ................... 5, 36, 63

Green ........................... 137

Guinea pigs and rabbits ......... 119

Gummite ....................... 12

Gutton .......................... 98

Geitel— conductivity in the air,
etc ......................... 38, 68

Geitel— emanation from the air.. 66
Geitel— radio-active emanation

from the air, soil, etc 66

Geitel— radio-active substances of
the air in the mountains and

level sea 139

Geitel— star effects from soil em-
anations, on Sidot's screen 72

Geitel— sulphides 55

Geitel — uranium 16

Geitel— uranium rays 11

Giesel— emanating substances and

E Kays 90

Giesel's Emanium 62, 63

Giesel — exposure of arm to ra-
dium 115

Giesel— Penetrating power of po-
lonium radiation 53

Giesel— Polonium of 61

Giesel— radio-active lead 60

Giesel — radio-activity of thorium 50
Giesel — radiations from an excited

piatinum wire 87

Giesel — action radium on plant

growth 116

Giesel — (3 or Cathode rays 38

Giesel— Bismuth and polonium so-
lution 55

Giesel— Temperature of impure ra-
dium salt 31

Giesel and Crookes— uranium 94

Giesel — water solution of radium
salts 28

Haitinger 99

Halzkuecht and Schwarz 117

Hallopean and Gadaud 119

Hammer 33

Hardy 45

Haschek 28

Heat— disengagement by radium. 30

Heiustadt 117

Helium 52, 77

Helium— from radium 98

Helium— minerals 77

Helium— spectrum 84

Heller 117

Heinptinne, De 43

Henning 76

Henry 8, 10

Hertz 5, 6

Heydweiller 92

Himstedt 66, 67

Hofmann 9, 11, 114

Hofmanu and Strauss 58

Hofmann and Strauss, Broggerite 59
Hofmaun and Wolf.., .. 60

158

INDEX.

Hofmann and Zerbtm. .48, 50, 58, 98

Holkin 129

Holzknecht 120

Huggins, Win. and Mary 83

Hydrogen, color of light, produc-
ed by electric discharge in 2

Hydrogen, weight of atom 5

Hyperaemia 133

Idiosyncrasy of patients 131

Impure radium, temperature 30

Inactive thorium 1°7

Induced radio-activity 87, 88

Induced radio-activity, Hypo-

. . 93

theses

Induced radio-activity—explana-
tion of

Influence of radium emanations ^
on bodies .................... "°

Intensity of the current, meas-
urement of .................... 1"

Intensity of radiation ........... 18

lonization of gases ....... . ..... 7, 8

Ionizer— Piffard's spark ......... 151

Ionizing rays ................... 95

Javal ........................... HO

Joachimsthal .................... 20

Johanngeogenstadt .............. 20

Joly ............................ 106

Kauri gum, photographic action
of Becquerel rays through ...... 13

Kelvin ........... 11, 68, 96, 100, 105

Knett ........................... 65

Kunz ................. 1 ....... 24, 34

Kunz and Baskerville, Tiff any ite
diamond ...................... 34

Kunzite ...................... 30, 74

L
Laborde ............... 30, 31, 96, 100

Laborde— heat .................. 96

Laborde — Impure radium, temper-
ature of ...................... 30

Lake (Stahmer & Co.)— patent. .. 61
Larmor ......................... 109

Law for unconflned spaces ....... 91

Le Bon ........................ 9

Lernly .......................... 51

Lenard ........................ 5, 6

Leuard rays .................... 6

Lenard's tube .................. 6

Lichtenthaeler .................. 63

Lieber ........... . . 125, 133

Lieber's aluminum tube for ra-
dium 125

Lieber's apparatus for application

of radium compounds 133

Limiting current 18

Lockhart 74, 77, 101

Lockwood 23, 25

Lodge 142

Lorentz 109

Lower organisms 120

Lowry 103

Luniiere 9

Luminescence 3

Lupus patient, Danlos Ill)

Lupus hypertrophicus 120

Lyster 127

Maclntyre 127

MacKenzie 127

Magnet, action of upon cathode

rays 3, 77

Magnetic field, action of upon ft

rays 14

Magnetic field, action of upon a-

rays 15

Mai de mer 138

Manning 137

Marckwald 27, 60, 61

Marckwald, character of polonium 55

Martiudale 105

Mass of cathode rays 5

Maxim . . .96, 97

McClelland 90

McClung 94

McLennan 102

McLennan and Burton 65, 66, 67

Mechanical action of cathode rays 4

Melauo— sarcoma 122

Mendel ejeff 29, 100

Mendelejeff, at. wt. tellurium.... 62

Metals, conduct of 87

Method for showing disengage-
ment of heat by radium 30

Method of obtaining radiographs. 42

Metzenbaum 92, 135, 140

Metzger 51

Meyer and Von Schweidler 38

Mice 128

Microbes 136

Miethe 11

Miner, H. S., radio-activity of th. 63
Modern Crookes tube for X-Ray

work 8

Molecular change 103

INDEX.

Moles 110

Momizite 20

Morton 122, 133, 139, 140

Morton's method for saturation of

water with emanations 139

Mouth 12^

Mucous Membrane, epithelioma. .145
Muller 66

Nagel 117

Necrosis 121

Necrotic ulcer 123

Nerve cell— disintegration from

Becquerel rays 129

Neuralgia 128

Newtonian theory 5

Nicol's prism 14

Niobite 20

Nitrogen, color of light produced

by electric discharge in 2

N C. uraninite (gummite) action

through 12

Norwegian gadolinite, orthite, etc. 49

Norwegian gadolinite, etc 99

Niewenzlowsky 9

Optic Nerve 117

Orangite 20

Orloff 45

Other sources of radio-activity.. 65

Owens 69

Oxygen, conversion into ozone,

etc 44

Oxygen, effect of radium on 44

Ozone . .102

Pacini 29

Paillat 43

Paralysis, facial 128

Paul, Edward 139

Pectolite 74

Pellini 62

Penetrability of radium emana-
tions • 33

Penetration of radium rays 32

Pegram 52, 87, 149

Pentadecylparatolylketone 6

Perrin 5, 43, 103

Pfahler 145

Pf eiff er 136

Phillips 23, 25

Phimosis scytitis 127

Phosphorescence . 7

Phosphorescence caused by eman-
ation of radium 82

Phosphorescing substances 10

Phosphorus, ionizing, effect of . . . 19

Photographic method 41, 52

Photographic plate, action of Len-

ard rays upon the 6

Photographic plate, action of

Roentgen rays upon the 6

Photographic plate, action of
phosphorescing substances upon

the 9

Photographic plate, action of

"black light" upon the 9

Photographic plate, action of

flourescing substances upon the. 10
Photographic plate, action of

uranium and its salts upon the. 11
Physiological action of radio-ac-
tive substances 115

Piffard— rendering water radio-
active (?) 93

Piffard's Electroscope 150

Piffard rays 148

Piffard ray s— skin 151

Piffard rays — uterine cancer 152

Piffard's spark— ionizer 151

Piffard's ultra-violet lamp 149

Pisani 21

Pitchblende.... 13, 15, 20, 31, 53, 127
Pitchblende— occurrence of, com-
position of 22

Pitchblende, Bohemian 48

Plant growth 116

Plate Condenser 17

Platinum-indium, Fusion of 4

Platinum— removal of activity of 86

Plimmer 130

Plucher 2

Polarization 14

Polonium 22, 47

Polonium, a- rays of 41

Polonium— Precipitation of 26

Polonium, methods of separation 53
Polonium radiation— less than ra-
dium 53

Polonium— not new element (?)... 54

Polonium nitrate 54

Polonium — radiferous bismuth .... 91
Polonium rays— photographic ef-
fect 54

Pozzi and Zimmerman 128

Precht 28, 29, 31, 62

Prescott 137

Projection of rays 39

i6o

INDEX.

Psoriasis 120

Pusey 128, 129, 143

Pzibram 20

Quartz electric balance 17

Quartz, photographic action of
Becquerel rays through 13

Radiant matter 4

Radiation, intensity of 18

Radiation from radium— method

of using 130

Radiations of radinm 39

Radio-active Elements, no. of.... 04
Radio-active Elements — method of

distinguishing 64

Radio-active emanations and sec-
ondary radio-activity 69

Radio-active lead 58

Radio-active lead— at. wt 59

Radio-active lead— chromate of... 59 j
Radio-active lead— spark spectrum 59
Radio-active phenomena— theories

of 94

Radio-activity— a detectable prop-
erty 30

Radio-activity and magnetism. .. .108

Radio-activity—cause of 101

Radio-activity— Curie's theory. . .100

Radio-activity, excited 85

Radio-activity, Hypotheses for in-
duced 93

Radio-activity—induced ^ hypothe-
ses 93 I

Radio-activity—other sources of. . 65
Radio-activity— Phenomenon capa-
ble of measurement 18

Radio-activity — Simplest means of

detection of (Note) 25

Radio-activity— Theory of 101

Radio-activity of minerals com-
pared with each other 20

Radio-activity of uranium com-
pounds compared with each

other 19

Radio-tellurium 60

Radio-active Thorium 49

Radio-diaphane 134, 135

Radio-tellurium 60

Radiograph of Al. metal by Bec-
querel 12

Radiographs of a fish 37

Radiograph of gold fish 88

Radiographs— methods of obtain-
ing 42

Radiograph with pitchblende

(Buckwalter) 15

Radiograph with pitchblende (Col-
lier) 13

Radium— amt. required 40.000 h.

p. energy emission 81, 82

Radium— analgesic action 128

Radium— animal tissue, hair, bone.

etc 118

Radium— at. wt. of 28, 29

Radium— Austria. United States. . 25

Radium— bacilli 136

Radium — bacterial cultures 136

Radium— B— Diphtheria 137

Radium-blood 139

Radium— capsule in between

teeth 134

Radium— carcinoma of oesophagus. 121

Radium— chemical action 43

Ujiilium— chloride, bromide, etc. . 28

Radium — corneal opacity 118

Radium— curdling of milk 138

Radium — cutaneous lesions 144

Radium — deep seated diseases. . .134

Radium — "De — emanated" 75

Radium — disengagement of heat

by 30

Radium — eczema, psoriasis 124

Radium — Effect on Thxiringian

glass, willemite, kunzite 30

Radium— epithelioma tongue 129

Radium— etiology of cancer 130

Radium— exhaustion 106

Radium— exposure 131

Radium salts— extraction 26

Radium— extraction and properties 22

Radium— eye 116

Radium— facial neuralgia 128

Radium— flexures cerebro-spinal

system 128

Radium — germicidial agent 139

Radium — glacoma 118

Radium — guinea pigs, rattbits, etc. 119

Radium — Luminosity of 30

Radium— Lungs 138, 139

Radium— Hyperaemia 133

Radium— lupus . . 118

Radium— lupus, rodent ulcer, etc. .122

Radium— nial de mer 138

Radium— malignant diseases 122

Radium — mice 128

Radium— moles . ..116-

INDEX.

161

Radium— neoplasm, etc 129

Radium— nervous system 129

Radium— not an element (?)

Wiukler 103

Radium — non-emanating 76

Radium — cancers, oesophageal ...135

Radium — optic nerve 117

Radium— Phirnosis scytitis 127

Radium— Plant growth 116

Radium— power dilating vessels.. 141

Radium — Preservation food 138

Radium — Radiations from 3 rays. 36

Radium— removal of hair 138

Radium— retina 117, 118

Radium— rodent ulcer 127

Radium— sclerotic 118

Radium— Secondary activity of... 43

Radium— seed germination 138

Radium— skin 116

Radium— Solar radiation 107

Radium— Spectrum 28

Radium — spine young animals. .. .115)

Radium— stricture 135

Radium— spasms 136

Radium— Temperature of impure

salt 30

Radium— Transformation prod-
ucts 113

Radium— Tuberculosis

Radium— ulcers 123

Radium — uterus, rectum and

mouth 129

Radium— Wart 116

Radium bromide— and actinium

oxide 57

Radium bromide 300,000 activity 34
Radium bromide— action on plants. 136
Radium bromide— effect ^>hoto

plate 29

Radium bromide treatment 121

Radium burn 116

Radium Chloride treatment. .119, 128

Radium clock— Strutt's 105

Radium D 114

Radium E 114

Ra-Em 103

Radium emanations— changes in.. 114
Radium emanations, influence on

bodies 78

Radium exhibit at St. Louis 25

Radium in treatment of skin dis-
eases 124

Radium preparations— application. 122

Radium sore, Becquerel 115

Radium sore— scar from . ..116

Radium X 77

Radium salts and heat 30

Radium salts— assumption of color 28
Radium salts— immersion of bis-
muth, etc 55

Radium salts— physical properties

of 27

Railway tube 4

Ramsay 141

Ramsay— electrons 112

Ramsay— extraction of active body
like thorium from Ceylon min-
eral 52

Ramsay and Soddy 84

Rassinghal and Gimingham 75

"Ray" and corpuscles 36

Rays— Piffard 148

Rays— types 36

R E 96

Rectum 129

Rehus 116

Residual activity 86

Retina 117

Richartz 102

Riecke, atoms 97

Richartz— ozone 102

Rodent ulcer 127

Robarts 127

Rollins 119

Rontgen 6, 7, 18, 85

Rontgen's first tube 7

Rontgen Rays. .6, 13, 18, 142, 145, 146

Rontgen Rays— and the eyes 117

Rontgen tube 6

Ruga scytitis 127

Runge 28, 29, 31, 53, 111

Runge and Precht— emanium 62

Rurio— Jicinsky 144

Rutherford— heat effect of radium

emanations

Rutherford— Transformation prod-
ucts radium 112

Rutherford and Soddy, condensa-
tion of emanations 79

Rutherford and Soddy— helium ... 98

Rutherford— radium D 114

Rutherford and Soddy— theory of.108
Rutherford - fi rays and y rays. 101
Rutherford and Thomson— radium

and uranium atom 100

Rutherford— vs. Curie 95

Rutherford and McClung— energy

ionizing rays 94

Rutherford — disappearance radium
emanation , . 91

INDEX.

Rutherford and Barnes— Heat
emissions, etc., radium emana-
tions 81, 89

Rutherford — activity dust particles 87

Rutherford— emanation X 86

Rutherford and Soddy, helium 84

Rutherford and Soddy— condensa-
tion temperatures, thorium and

radium emanations . . . . ; 79

Rutherford and Brooks — emana-
tion of radium 79

Rutherford and Soddy — effect

moisture on emanations 75, 76

Rutherford and Soddy— emanation

of radium sparked in glass tube 79
Rutherford and Soddy— emanating

power of thorium 74

Rutherford — condensation of ra-
dium emanations 74

Rutherford — thorium "emanations"

69, 70
Rutherford— heat loss of earth

and radium 68

Rutherford and Allan— excited ra-
dio-activity 65

Rutherford — Thorium, power of

inducing activity 51

Rutherford and Soddy— Thorium. . 50
Rutherford— uranium radiations

complex 48

Rutherford— y rays 41

Rutherford — a rays 40

Rutherford— uranium a and ft rays

Rutherford— types of rays of ra-
dium radiations " 36

Rutherford — electroscope 20

Rutherford— Law of conductivity

of air 18

Rutherford— energy from uranium 16
Rutherford and Soddy— a rays. ... 15

Rutherford— uranium rays 11, 14

Rutherford— Rontgeu rays 13

Saake 139

Saginac 85

Sarcoma— giant cell 132. 143

Samarskite 13, 20

Saturation, current of 18

Scar from radium sore. 116

Schamberg 129

Schenck, theory of radio-activity. 102

Schmidt 19, 48

Schmidt— Nielsen . ..137

129

68
117

38
118

Scholtz

Schuster

Schwarz

Schweidler

Sclerotic

Screen— zinc, sulphide, barium,

platino-cyanide . ............... 29

Secondary Radio-activity ........ 69

Secondary radio-activity of metals 85
Septic ulcers ................... 127

Sharpe .......................... 338

Sichel .......................... 128

Sidot ........................... 9

Sidot's Blende— eiiianium exp.... 62

Skin— effect radium on ........... 116

Skiagraph of tools .............. 32

Skin ............................ 115

Skin diseases— treatment of ...... 124

Smolan De ..................... 11

Soddy— a rays .................. 15

Soddy— effect moisture on emana-

tions ....................... 75, 76

Soddy— emanating power thorium 74
Soddy— emanation from radium

sparked in glass tube, thorium

emanations .................... 79

Soddy— helium .................. 84

Soddy— radio-active elements .... 64

Soddy— radium bromide ......... 71

Soddy— radium salt and tubercu-

losis ...................... 138, 139

Soddy— Theory of, and Rutherford . 10S
Soddy— Thorium X ......... . ..... 50

Soddy— uranium radiations ...... 47

Soddy— uranium rays ............ 14

Solar radiations— and radium ---- 10(5

Solar rays ...................... 146

South American Mineral ....... 52, i)9

Spark Ionizer, Piffard's. . . ...... 151

Spasms ......................... 130

Spies ........................... 11

Spine ........................... 119

Spinthariscope ............. 72, 73, 97

Spinthariscope of Crookes ........ 72

Spodumene ...................... 74

Stahmer & Co.— Lake. . ." ........ 61

Staphylococc'us bacillus ......... 130

Strauss ......................... 11

Strauss— lead sulphate, etc ..... 58, 59

mercury ....................... 66

Streptococcus bacillus .......... 136

Strutt— a rays .................. 40

Strutt-^-emanations from metallic
Strutt— examination of minerals. 77
Strutt— y rays .................. 42

INDEX.

163

Strutt— radiations of radium 33

Strutt's Radium Clock 105

Sudborough 44

Sulphides— emissing ft rays 55

''Tailings" 23

Tantalite 20

Taudin and Chabot 103

Temperature, effect of upon the

radiations 18

Theory, electric single fluid of

Franklin 5

Theories of radio-active phenome-
na 94

Therapeutic application— radio-ac-
tive substances 115

Thompson, S. P G

Thomson— Cambridge tap water ... 65
Thomson— cause emission of en-
ergy from radium... 96

Thomson— Crookes ray 5, 104

Thomson— radio-active matter,

Becquerel's Hypothesis 94

Thomson — Radiation of metals. . . .106

Thomson — Rontgen rays 13

Thomson and Rutherford— laws of

conductivity of air 18

Thomson and Rutherford— ura-
nium atom and radium 100

Thomson, Larmor and Lorentz —

atom complicated 109

Thorium 36, 41, 48

Thorium and radium — de-emanated 75

Thorium — and septic ulcers 127

Thorium— "de-emanated" 75

Thorium— emanation X 87

Thorium— from mouazite and con-
stituents 52

Thorium— from South American

Mineral 52

Thorium— inactive 107

Thorium, occurrence with ura-
nium 19

Thorium — radio-active 49

Thorium— radio-activity of 19

Thorium— radio-active from mona-

zite 52

Thorium— X 49, 77

Thorium— X Rutherford's 107

Thorite 20

Thuringian glass 30. 74

Tiger eye, photographic action of

Becquerel rays through 13

Tiffanyite 74

Tissue 119, 130

Tissue, hair, bone, etc 118

Titanium— separation 56

Topler pump 112

Tongue and tonsil 129

Tonsil and tongue 129

Tourmaline 14

Townsend 18

Tracy 138

Transformation products of ra-
dium 113

Transmutation Ill

Traubenberg 67

Troost 9

Tuberculosis 138, 145

Tuberculosis, germicidial agent

for 139

Tumors 145

Tur 120

Turquoise, photographic action of

Becquerel rays through 13

Ty phosus bacillus 13(5

Tyrer 52

Ultra— violet rays 146, 147

U. S. Geog. Survey Expert (Kunz) 24
Urauinite (See also Pitchblende),

12. 13

Uranium— activity by the electro-
meter 36

Uranium 41, 46, 53

Uranium— certain minerals possess
a greater intensity than the

metal uranium itself 2.1

Uranium — extraction of from

"Tailings" 23

Uranium, metal 20

Uranium — occurrence with thorium 19

Uranium— radio-activity of 19, 51

Uranium— radio-activity not con-
stant 47

"Uranium rays" 11

Uranium— residues 26

Uranium — salts of in sunlight.... 11

Uranium and thorium 21

Uranium compounds, activity of

different 19

Uranium, metal 20

Uranium, potassium, sulphate.... 10

Uranium salts 10, 11

Uranium salts, activity of, a rays 16

Ur, Ur X,*Ra Em, etc 103

Ur X 47

Uterus . ...M29

164

INDEX.

Vaii Aubel 43

Van Buren 137

Velocity of cathode rays 5

Villard 41

Voller 67

Von Lerch . 87, 93

.145
.115
. 70
.110
29
. 27
. 63

Walker

Walkhoff

Wallstade

Wart

Watts

Wedekind

Welsbach Light Co

Wilson 41

Wiedemann 3, 5, 150

Wiedemann, Luminescence 3

Wien 36

Wigham 136

Wilbert 144

Willcock 45

Willemite 30, 148

Willemite and calcite 147

Williams 123, 130, 133, 143

Wilson, C. T. R 65

Wilson, W. E 100

Winkler 103

Winkler and Hofiuanu 60

Wolf, radio-active lead 60

Worms . ..120

Xenotime 20

"X-light" 143

X-Rays 6, 94, 145, 140

X-Rays Carciuomata 145

X-Ray— cancer 146

X-Ray — epithelioma mucous mem-
brane 145

X-Ray — Lupus, acne, etc 146

X-Ray — sarcoma 143

X-Ray treatment 131

X-Ray treatment (Williams) 143

X-Ray— tuberculosis and carcin-
nouia . . 145

Zeisler 146

Zerban 9, 52, 99

Zerban— activity thorium 48

Zerban— at. wt. actinium (?) 58

Zerban— Primary activity thorium 50
Zerban— South American Mineral. 52
Zerban— Th. from S. Am. Mineral. 99
Zerban— thorium from uranium.. 98

Zimmern 128

Zinc Sulphide 74

Zinc sulphide, phosphorescent 9

Zinc sulphide, hexagonal 9

Zinsser ..137

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